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Автор(ы)	Название	Год	Журнал	DOI
Ettah E.B., Minakova K., Ishaje M.E., Sirenko V.	On the interplay of thermodynamic and structural properties of LiZn-based half-Heusler alloys [Abstract] [BibTeX]	2023	Low Temperature Physics Vol. 49(11)	DOI
Abstract: The half-Heusler LiZnX (X = As, P, and Sb) alloys have gained a significant attention due to their exceptional thermoelectric and magnetic properties, making them a promising material for various applications. In this study, we employ density functional theory to investigate the data on structural and thermodynamics properties of the LiZnX (X = As, P, and Sb) half-Heusler alloys. First-principles calculations as implemented in quantum Espresso simulation software were used. We observed that LiZnX (X = As, P, and Sb) will be easily compressed due to the small value of its bulk modulus. We obtained that the structure is stable and corresponds a half-Heusler crystal one. The Debye model correctly predicts the observed low-temperature dependence of heat capacity, which is proportional to the Debye T3 law. At room temperature, Debye specific heat Cv = 70 J / (K·N·mol).
BibTeX: @article{Ettah2023, author = {Ettah, E. B. and Minakova, K. and Ishaje, M. E. and Sirenko, V.}, title = {On the interplay of thermodynamic and structural properties of LiZn-based half-Heusler alloys}, journal = {Low Temperature Physics}, year = {2023}, volume = {49}, number = {11}, doi = {http://dx.doi.org/10.1063/10.0021371} }
Grechnev G.E., Lyogenkaya A.A., Desnenko V.A., Fedorchenko A.V., Panfilov A.S.	Magnetic and magnetoelastic properties of antiferromagnet FeGe₂ [Abstract] [BibTeX]	2023	Low Temperature Physics Vol. 49(9), pp. 1025-1030	DOI
Abstract: The magnetic susceptibility χ of single-crystal antiferromagnet FeGe₂ (T_N = 289 K) was measured in the temperature range from 4.2 to 300 K in a magnetic field H up to 40 kOe applied along the main crystallographic axes. For the antiferromagnetic (AFM) state at low temperatures, a strong increase in χ is observed with increasing H applied along the [100] axis, which reaches saturation at H ≥ H₀ ∼ 11 kOe. It is assumed that this behavior is associated with a field-induced change in the AFM domain structure, and the single-domain state is realized in a field above H₀ with the AFM axis perpendicular to the field direction. The study of χ under the uniaxial P_a and uniform P pressures in a wide temperature range has revealed an anomalously large increase in χ in AFM state with increasing uniaxial pressure for P_a \|\| H \|\| [100] at H ≪ H₀. The observed growth of χ saturates at pressure P_a ≥ P_a^∗ ≃ 1.5 kbar and suggests the formation of the single-domain state for the above conditions. The values of uniform pressure effect on χ was found to lie in the range dlnχ / dP = - (2-3) Mbar^–1, being weakly dependent on the magnetic state and field direction. In addition, the uniform pressure effect on the transition temperature between two AFM structures in FeGe₂, T_M ≃ 263 K, was found to be weak.
BibTeX: @article{grechnev2023, author = {Grechnev, G. E. and Lyogenkaya, A. A. and Desnenko, V. A. and Fedorchenko, A. V. and Panfilov, A. S.}, title = {Magnetic and magnetoelastic properties of antiferromagnet FeGe₂}, journal = {Low Temperature Physics}, year = {2023}, volume = {49}, number = {9}, pages = {1025-1030}, doi = {http://dx.doi.org/10.1063/10.0020594} }
Fil V.D., Fil D.V., Zvyagina G.A., Bilych I.V., Zhekov K.R.	Villari effect in FeSe1-xSx [Abstract] [BibTeX]	2023	Low Temperature Physics Vol. 49(9), pp. 1043-1049	DOI
Abstract: Acoustoelectric transformation (occurrence of electromagnetic radiation under the action of an elastic wave) in a FeSe0.925S0.075 crystal in the presence of an external magnetic field has been studied. It is shown that the application of the magnetic field along the direction of propagation of the elastic wave leads to a rotation of the plane of polarization of the emitted electromagnetic wave. The physical mechanism is that the elastic deformation leads to the appearance of a non-diagonal component of the magnetic susceptibility and to the generation of an additional alternating magnetic moment perpendicular to the external magnetic field and to the elastic displacement. The observed features are interpreted as a manifestation of the Villari effect. A phenomenological description of the experimental results is presented. The observed effect shows that the symmetry of the low-temperature FeSe1–xSx phase belongs to the triclinic syngony.
BibTeX: @article{Fil202309, author = {Fil, V. D. and Fil, D. V. and Zvyagina, G. A. and Bilych, I. V. and Zhekov, K. R.}, title = {Villari effect in FeSe1-xSx}, journal = {Low Temperature Physics}, year = {2023}, volume = {49}, number = {9}, pages = {1043-1049}, doi = {http://dx.doi.org/10.1063/10.0020597} }
Panfilov A.S., Desnenko V.A., Lyogenkaya A.A., Grechnev G.E., Shitsevalova N.Y.	Probing the bulk valence of Sm in SmB6 by studying the magnetic susceptibility under pressure [Abstract] [BibTeX]	2023	Low Temperature Physics Vol. 49(9), pp. 1037-1042	DOI
Abstract: For one of the most famous and widely investigated intermediate-valence compound SmB6, we report the results of a precise experimental study of the pressure effect on magnetic susceptibility χ. The measurements of χ(P) were carried out under helium gas pressure P up to 2 kbar at fixed temperatures 78 and 300 K using a pendulum-type magnetometer. The observed pressure effect value, d lnχ/dP ∼ –6 Mbar–1, demonstrates a noticeable decrease in susceptibility under pressure, which is weakly dependent on temperature used. From model analysis of the experimental data, combined with the supplemented LSDA + U calculations of the electronic structure and van Vleck paramagnetism of the band states of SmB6, we have estimated the value of the initial pressure derivative for the intermediate valence of Sm. It is consistent with the literature data obtained by other methods and indicates an increase in valence with increasing pressure. It was shown that the valence of Sm and its pressure dependence are closely related to the detailed characteristics of the conduction band and 4f states.
BibTeX: @article{Panfilov202309, author = {Panfilov, A. S. and Desnenko, V. A. and Lyogenkaya, A. A. and Grechnev, G. E. and Shitsevalova, N. Yu.}, title = {Probing the bulk valence of Sm in SmB6 by studying the magnetic susceptibility under pressure}, journal = {Low Temperature Physics}, year = {2023}, volume = {49}, number = {9}, pages = {1037-1042}, doi = {http://dx.doi.org/10.1063/10.0020596} }
Zvyagin A.A., Slavin V.V., Zvyagina G.A.	Enhancement of superconducting fluctuations in a correlated electron system coupled to the lattice [Abstract] [BibTeX]	2023	Physical Review B - Condensed Matter and Materials Physics Vol. 108, pp. 045428	DOI
Abstract: Using the exact Bethe ansatz solution, a one-dimensional correlated electron system coupled to the lattice is considered. Electrons belonging to two orbital bands interact via the exchange coupling. It is shown that the coupling to the lattice strains can produce a phase transition to the state in which the degeneracy in the orbital filling is removed. In such a state the formation of superconducting correlations is enhanced. The influence of the external magnetic field on the transition is studied.
BibTeX: @article{Zvyagin202307, author = {Zvyagin, A. A. and Slavin, V. V. and Zvyagina, G. A.}, title = {Enhancement of superconducting fluctuations in a correlated electron system coupled to the lattice}, journal = {Physical Review B - Condensed Matter and Materials Physics}, publisher = {American Physical Society}, year = {2023}, volume = {108}, pages = {045428}, doi = {http://dx.doi.org/10.1103/PhysRevB.108.045428} }
Zvyagin A.A., Zvyagina G.A.	Influence of the ac magnetic field on the elastic and electric characteristics of a quantum paramagnet [Abstract] [BibTeX]	2023	Low Temperature Physics Vol. 49(6), pp. 724-729	DOI
Abstract: It is shown that electric, piezoelectric, and elastic characteristics of the orthorhombic quantum paramagnet depend on the applied ac magnetic field, collinear to the dc one. The dependence is due to the renormalization of the quadrupole spin susceptibility. In the dynamical regime, the quadrupole susceptibility oscillates with the frequency of the ac field, and with the Rabi-like frequency. In the steady-state regime, the quadrupole susceptibility oscillates with the frequency of the ac field only about the renormalized with respect to the initial one value. That renormalization can change the values of the electric, piezoelectric, and elastic characteristics of the system.
BibTeX: @article{Zvyagin202306i, author = {Zvyagin, A. A. and Zvyagina, G. A.}, title = {Influence of the ac magnetic field on the elastic and electric characteristics of a quantum paramagnet}, journal = {Low Temperature Physics}, year = {2023}, volume = {49}, number = {6}, pages = {724-729}, doi = {http://dx.doi.org/10.1063/10.0019428} }
Zvyagin A.A., Zvyagina G.A.	Piezomagnetic and electromagnetic effects in the paramagnetic phase of antiferromagnets [Abstract] [BibTeX]	2023	Low Temperature Physics Vol. 49(6), pp. 730-732	DOI
Abstract: Using the Landau theory of phase transitions, it is explained how the piezomagnetic and electromagnetic effects can exist at temperatures higher than the ordering temperature in antiferromagnets.
BibTeX: @article{Zvyagin202306ii, author = {Zvyagin, A. A. and Zvyagina, G. A.}, title = {Piezomagnetic and electromagnetic effects in the paramagnetic phase of antiferromagnets}, journal = {Low Temperature Physics}, year = {2023}, volume = {49}, number = {6}, pages = {730-732}, doi = {http://dx.doi.org/10.1063/10.0019429} }
Fil V.D., Fil D.V., Zvyagina G.A., Bilych I.V., Zhekov K.R.	Piezomagnetism in a mixed state in FeSe-based superconductors [Abstract] [BibTeX]	2023	Low Temperature Physics Vol. 49(5), pp. 614-618	DOI
Abstract: The acoustoelectric transformation (AET) in the mixed state of FeSe-based superconducting chalcogenides was studied. Dependence of the AET signal on the magnetic field obtained at the initial stages of flux penetration shows a behavior that can be explained only if the piezomagnetism is included in the consideration. This argues that these crystals belong to the class of compounds with broken time-reversal symmetry and are in a state of hidden magnetic order.
BibTeX: @article{Fil202305, author = {Fil, V. D. and Fil, D. V. and Zvyagina, G. A. and Bilych, I. V. and Zhekov, K. R.}, title = {Piezomagnetism in a mixed state in FeSe-based superconductors}, journal = {Low Temperature Physics}, year = {2023}, volume = {49}, number = {5}, pages = {614-618}, doi = {http://dx.doi.org/10.1063/10.0017823} }
Zvyagin A.A., Slavin V.V., Zvyagina G.A.	Manifestation of spin nematic ordering in the spin-1 chain system [Abstract] [BibTeX]	2023	Physical Review B - Condensed Matter and Materials Physics Vol. 107, pp. 134421	DOI
Abstract: Spin-1 chain material is considered. Recently, it was predicted that the spin nematic ordered phase can be realized due to the spin-elastic coupling. In this study we show that the appearance of the spin nematic ordering and phase transitions to such ordered states can be studied using magneto-acoustic experiments. One can observe such phases and phase transitions considering relative changes of the velocity of sound (related to the changes of the elastic modulus of the crystal) as a function of temperature and the external magnetic field. It is shown that those relative changes are proportional to the spin quadrupole susceptibility of the system. The results are obtained using the exact Bethe ansatz solution and Quantum Monte Carlo simulations for several typical values of the biquadratic spin-spin exchange interaction and for various values of the spin-elastic coupling and elastic modules.
BibTeX: @article{Zvyagin202304, author = {Zvyagin, A. A. and Slavin, V. V. and Zvyagina, G. A.}, title = {Manifestation of spin nematic ordering in the spin-1 chain system}, journal = {Physical Review B - Condensed Matter and Materials Physics}, publisher = {American Physical Society}, year = {2023}, volume = {107}, pages = {134421}, doi = {http://dx.doi.org/10.1103/PhysRevB.107.134421} }
Pashkevich Y.G., Fertman E.L., Fedorchenko A.V., Vieira D.E.L., Neves C.S., Babkin R., Lyogenkaya A.А., Tarasenko R., Tkáč V., Čižmár E., Feher A., Salak A.N.	Magnetic ordering in Co²⁺-containing layered double hydroxides via the low-temperature heat capacity and magnetisation study [Abstract] [BibTeX]	2023	Applied Clay Science Vol. 233, pp. 106843	DOI
Abstract: The low-temperature heat capacity and the magnetisation of Co²⁺_nAl³⁺ layered double hydroxides (LDH) with the cobalt-to-aluminium ratio n = 2 and 3 and intercalated with different anions have been studied in a wide range of magnetic fields up to 50 kOe. The heat capacity, C(T), was found to demonstrate a Schottky-like anomaly observed as a broad local maximum in the temperature dependence below 10 K. The effect is caused by a splitting of the ground-state Kramers doublet of Co²⁺ in the internal exchange field and correlates with magnetic ordering in these LDH. In low applied fields, the temperature-dependent dc magnetic susceptibility demonstrates a pronounced rise, which is associated with an onset of magnetic ordering. Both the heat capacity anomaly and the magnetic susceptibility peak are more pronounced for the LDH with n = 2 than for those with n = 3. This feature is associated with an excess of the honeycomb-like CoAl coordination (which corresponds to a 2:1 CoAl ordering) over the statistical cation distribution in Co₂Al LDH, while a rather random cobalt-aluminium distribution is typical for Co₃Al LDH. The temperature of the Schottky-like anomaly measured in a zero field is independent of the interlayer distance. Application of the magnetic field results in a widening of the anomaly range and a shift to higher temperatures. The observed experimental data are typical for a cluster spin glass ground state.
BibTeX: @article{pashkevich2023, author = {Pashkevich, Y. G. and Fertman, E. L. and Fedorchenko, A. V. and Vieira, D. E. L. and Neves, C. S. and R.Yu. Babkin and Lyogenkaya, A. А. and Tarasenko, R. and Tkáč, V. and Čižmár, E. and Feher, A. and Salak, A. N.}, title = {Magnetic ordering in Co²⁺-containing layered double hydroxides via the low-temperature heat capacity and magnetisation study}, journal = {Applied Clay Science}, year = {2023}, volume = {233}, pages = {106843}, doi = {http://dx.doi.org/10.1016/j.clay.2023.106843} }
Feodosyev S.B., Sirenko V.A., Syrkin E.S., Manzhelii E.V., Bondar I.S., Minakova K.A.	Localized and quasi-localized energy levels in the electron spectrum of graphene with isolated boron and nitrogen substitutions [Abstract] [BibTeX]	2023	Low Temperature Physics Vol. 49(1), pp. 30-37	DOI
Abstract: Based on the calculation and analysis of local Green’s functions of impurity atoms of low concentration in a two-dimensional graphene lattice, the conditions for the formation and characteristics of local discrete levels with energies lying outside the band of the quasi-continuous spectrum and quasi-localized states with energies near the Fermi one are determined. Specific calculations were performed for boron and nitrogen impurity atoms, which can actually replace carbon in graphite and graphene nanostructures. For a boron impurity that forms local discrete levels outside the band of the quasi-continuous spectrum, sufficiently simple analytical expressions for the conditions for their formation, energy, intensity at the impurity atom, and damping parameter are obtained. An analysis of the formation of states quasi-localized on nitrogen impurities with energy near the Fermi level in graphene nanostructures was carried out.
BibTeX: @article{Feodosyev202301, author = {Feodosyev, S. B. and Sirenko, V. A. and Syrkin, E. S. and Manzhelii, E. V. and Bondar, I. S. and Minakova, K. A.}, title = {Localized and quasi-localized energy levels in the electron spectrum of graphene with isolated boron and nitrogen substitutions}, journal = {Low Temperature Physics}, year = {2023}, volume = {49}, number = {1}, pages = {30-37}, doi = {http://dx.doi.org/10.1063/10.0016473} }
Panfilov A.S., Grechnev G.E., Pashchenko V.A., Prabhakaran D.	Pressure effects on magnetic properties of LaMnO3 and YMnO3 [Abstract] [BibTeX]	2023	Low Temperature Physics Vol. 49(1), pp. 145-149	DOI
Abstract: The magnetic susceptibility χ of RMnO3 (R = La, Y) manganites was measured for paramagnetic phase as a function of the hydrostatic pressure P up to 2 kbar at some fixed temperature in the range from 78 to 300 K. A pronounced magnitude of the pressure effect dln χ/dP was found to be positive in sign for LaMnO3 and negative for YMnO3, both being strongly temperature dependent. Analysis of the experimental data, based on the Curie-Weiss behavior of χ(Τ), allowed to estimate the pressure derivative of the paramagnetic Curie temperature to be dΘ/dP = (0.25 ± 0.03) and -(2.4 ± 0.4) K/kbar for LaMnO3 and YMnO3, respectively.
BibTeX: @article{Panfilov202301, author = {Panfilov, A. S. and Grechnev, G. E. and Pashchenko, V. A. and Prabhakaran, D.}, title = {Pressure effects on magnetic properties of LaMnO3 and YMnO3}, journal = {Low Temperature Physics}, year = {2023}, volume = {49}, number = {1}, pages = {145-149}, doi = {http://dx.doi.org/10.1063/10.0016488} }
Feodosyev S., Sirenko V., Gospodarev I., Bondar I., Syrkin E., Minakova K.	Graphite and Graphene Nano-films: Phonons Localization and Propagation [Abstract] [BibTeX]	2022	2022 IEEE 3rd KhPI Week on Advanced Technology (KhPIWeek), pp. 1-6	DOI
Abstract: The nature of flexural rigidity of graphene monolayers and a formation of the quasi-flexural modes in a graphite and the graphene nano-films is explained. It is shown, that in the major part of the band of quasi-continuous spectrum, quasi-flexural modes do not practically couple with the modes polarized in the plane of the layer. The frequencies of propagone zone are determined for the phonons with various polarizations. The existence of high-frequency propagation zone is demonstrated for quasi-flexural phonons. The conditions for a formation of quasi-local vibrations and boson peaks are analyzed for modes with different polarization. The conditions for the formation of the quasi-local vibrations and boson peaks in the modes of different polarization are analyzed.
BibTeX: @article{feodosyev2022ii, author = {Feodosyev, S. and Sirenko, V. and Gospodarev, I. and Bondar, I. and Syrkin, E. and Minakova, K.}, title = {Graphite and Graphene Nano-films: Phonons Localization and Propagation}, journal = {2022 IEEE 3rd KhPI Week on Advanced Technology (KhPIWeek)}, year = {2022}, pages = {1-6}, doi = {http://dx.doi.org/10.1109/KhPIWeek57572.2022.9916495} }
Zvyagin A.A., Zvyagina G.A.	Grüneisen parameters in the quantum paramagnet with the magnetoelectric coupling [Abstract] [BibTeX]	2022	Low Temperature Physics Vol. 48(10), pp. 780-786	DOI
Abstract: It is shown theoretically that magnetic Grüneisen parameter for the quantum orthorhombic paramagnet manifests features similar to the ones observed in many-body quantum spin systems at critical points. For the paramagnet with the strong coupling between the spin and electric subsystems, we have introduced the electric Grüneisen parameter, which is the characteristic of the electrocaloric effect in the system. The low-temperature behavior of both Grüneisen parameters is determined by the crossover points of the spectrum of the quantum paramagnet.
BibTeX: @article{zvyagin2022ii, author = {Zvyagin, A. A. and Zvyagina, G. A.}, title = {Grüneisen parameters in the quantum paramagnet with the magnetoelectric coupling}, journal = {Low Temperature Physics}, year = {2022}, volume = {48}, number = {10}, pages = {780-786}, doi = {http://dx.doi.org/10.1063/10.0014019} }
Feodosyev S.B., Gospodarev I.A., Sirenko V.A., Syrkin E.S., Bondar I.S., Minakova K.A.	Features of the propagation of phonons in graphene nanostructures. Fast high-frequency phonons in a quasi-flexural mode [Abstract] [BibTeX]	2022	Low Temperature Physics Vol. 48(8), pp. 628-633	DOI
Abstract: The character of propagation in graphene nanostructures of quasi-flexural phonons, whose dispersion law differs from that of sound, is analyzed. Based on the calculation of the frequency dependences of the group velocities and the values of the path of quasiparticles for one period of oscillation, the frequency intervals are established at which: i) phonons propagate freely along all directions of reciprocal space - the propagon zone; ii) phonon propagation along some directions is impossible - diffuse zone; iii) phonons are localized at the nodes of the honeycomb lattice - the locon zone. A comparison is made with a similar classification of phonons in a three-dimensional crystal of cubic symmetry.
BibTeX: @article{feodosyev2022iii, author = {Feodosyev, S. B. and Gospodarev, I. A. and Sirenko, V. A. and Syrkin, E. S. and Bondar, I. S. and Minakova, K. A.}, title = {Features of the propagation of phonons in graphene nanostructures. Fast high-frequency phonons in a quasi-flexural mode}, journal = {Low Temperature Physics}, year = {2022}, volume = {48}, number = {8}, pages = {628-633}, doi = {http://dx.doi.org/10.1063/10.0012650} }
Bilych I.V., Zhekov K.R., Haidamak T.N., Zvyagina G.A., Fil D.V., Fil V.D.	Study of magnetoelastic interaction in MnF₂ by the acoustoelectric transformation method [Abstract] [BibTeX]	2022	Low Temperature Physics Vol. 48(7), pp. 537-544	DOI
Abstract: The mechanisms of magnetoelastic interaction in MnF₂ are studied using the method of acoustoelectric transformation. The temperature dependence of the piezomagnetic coupling coefficient and its anisotropy were determined in the antiferromagnetic phase. We observe a new effect consisting in the appearance of a non-diagonal component of the magnetic susceptibility tensor, which is proportional to the square of the order parameter, under the action of the shear wave. A phenomenological interpretation of the effect, which takes into account a small-angle rotation of the crystal lattice, is presented. In the paramagnetic state, the effect of acoustic deformation is reduced to the modulation of the diagonal component of the susceptibility tensor.
BibTeX: @article{bilych2022, author = {Bilych, I. V. and Zhekov, K. R. and Haidamak, T. N. and Zvyagina, G. A. and Fil, D. V. and Fil, V. D.}, title = {Study of magnetoelastic interaction in MnF₂ by the acoustoelectric transformation method}, journal = {Low Temperature Physics}, year = {2022}, volume = {48}, number = {7}, pages = {537-544}, doi = {http://dx.doi.org/10.1063/10.0011601} }
Panfilov A.S., Grechnev G.E.	Pressure effect on magnetic susceptibility of intermediate-valence compound YbInAu₂ [Abstract] [BibTeX]	2022	Low Temperature Physics Vol. 48(3), pp. 223-227	DOI
Abstract: The pressure dependence of the magnetic susceptibility of the intermediate-valence compound YbInAu₂ has been measured in the temperature range of 78-300 K, showing a strong and temperature-dependent increase in susceptibility under pressure. The initial analysis of the experimental data within the framework of the integer valence Coqblin-Schrieffer model has given certain estimates of the Kondo temperature and its pressure derivative, but did not allow to describe quantitatively the specific temperature dependence of the susceptibility itself. The Anderson impurity model with infinite Coulomb repulsion U, the main parameters of which are the position of the f level relative to the Fermi energy and its hybridization width, turned out to be more suitable to describe the obtained experimental data for YbInAu₂, indicating a strong dependence of the f-level position on the atomic volume.
BibTeX: @article{panfilov2022, author = {Panfilov, A. S. and Grechnev, G. E.}, title = {Pressure effect on magnetic susceptibility of intermediate-valence compound YbInAu₂}, journal = {Low Temperature Physics}, year = {2022}, volume = {48}, number = {3}, pages = {223-227}, doi = {http://dx.doi.org/10.1063/10.0009540} }
Zvyagin A.A., Zvyagina G.A.	Biaxial paramagnet: Manifestation of the electro-magneto-elastic coupling [Abstract] [BibTeX]	2022	Low Temperature Physics Vol. 48(3), pp. 212-222	DOI
Abstract: The effect of the coupling between the spin (magnetic), electric, and elastic subsystems of the biaxial paramagnetic crystal has been studied. Relative changes of the electric permittivity, piezoelectric modules, elastic modules, and the magnetic susceptibility of such a system have been calculated. It has been shown that the external electric field, polarized in the plane, perpendicular to the external magnetic field, depending on its polarization, can change the effective symmetry of the crystal, reducing it to the monoclinic symmetry, or enlarging it to the tetragonal (with one distinguished axis) one. Those changes of the symmetry manifest themselves in the special features in the behavior of various calculated characteristics of the paramagnetic crystal with coupled magnetic, electric, and elastic subsystems.
BibTeX: @article{zvyagin2022, author = {Zvyagin, A. A. and Zvyagina, G. A.}, title = {Biaxial paramagnet: Manifestation of the electro-magneto-elastic coupling}, journal = {Low Temperature Physics}, year = {2022}, volume = {48}, number = {3}, pages = {212-222}, doi = {http://dx.doi.org/10.1063/10.0009539} }
Feodosyev S.B., Gospodarev I.A., Sirenko V.A., Syrkin E.S., Bondar I.S., Minakova K.A.	Propagation and localization of phonons in graphite and graphene nanofilms [Abstract] [BibTeX]	2022	Low Temperature Physics Vol. 48(2), pp. 121-125	DOI
Abstract: The nature of flexural rigidity of graphene monolayers and the formation of the quasi-flexural modes in graphite and graphene nanofilms is explained. It is shown, that in the major part of the band of quasi-continuous spectrum, quasi-flexural modes do not practically couple with the modes polarized in the plane of the layer. The frequencies of the propagone zone are determined for the phonons with various polarizations. The existence of a high-frequency propagation zone is demonstrated for quasi-flexural phonons. The conditions for the formation of quasi-local vibrations and boson peaks are analyzed for modes with different polarization. The conditions for the formation of the quasi-local vibrations and boson peaks in the modes of different polarization are analyzed.
BibTeX: @article{feodosyev2022, author = {Feodosyev, S. B. and Gospodarev, I. A. and Sirenko, V. A. and Syrkin, E. S. and Bondar, I. S. and Minakova, K. A.}, title = {Propagation and localization of phonons in graphite and graphene nanofilms}, journal = {Low Temperature Physics}, year = {2022}, volume = {48}, number = {2}, pages = {121-125}, doi = {http://dx.doi.org/10.1063/10.0009291} }
Glamazda A.Y., Gnezdilov V.P., Lemmens P., Zvyagina G.A., Gudim I.A.	Raman scattering study of the rare-earth binary ferroborate Nd_0.75Dy_0.25Fe₃(BO₃)₄ single crystal [Abstract] [BibTeX]	2021	Low Temperature Physics Vol. 47(12), pp. 1011-1021	DOI
Abstract: We report comprehensive Raman scattering measurements on a single crystal of binary ferroborate Nd0.75Dy0.25Fe3(BO3)4 in the temperature range of 7-295 K with 532 nm (18797 cm-1) laser excitation. The performed analysis of the polarized Raman spectra revealed the bands assigned to phonon, magnetic, and electronic excitations. The temperature evolution of these quasiparticle excitations has allowed us to ascertain the intricate coupling and interplay between lattice, magnetic, and electronic degrees of freedom. Analysis of the measured Raman spectra made it possible to identify all A1 and E phonon modes predicted by the group-theoretical analysis. The splitting energies between the LO and TO components of the polar E phonons were determined. Below the magnetic ordering temperature of the Fe sublattice, TN, we have revealed a multiple peaked two-magnon excitation. Analyzing the temperature evolution of low-frequency modes in the spectra, we also identified modes that are associated with electronic transitions between the crystal field levels of the Nd3+ ions with ground-state 4I9/2 and of the Dy3+ ions with ground-state 6H15/2 multiplets. In addition to the already known temperatures of magnetic transitions, analysis of the temperature behavior of low-frequency phonon and electronic excitations made it possible to establish a temperature T* = 100 K, presumably associated with local distortions of the crystal lattice. The presence of this temperature is confirmed by our ultrasonic study. A group of intense bands observed in the frequency range 1700-2200 cm-1 has been associated with the mixed low-lying electronic Raman transitions 4I9/2→4I11/2 and the high-energy luminescence ones 4G5/2+2G7/2→4I9/2 for the Nd3+ ion.
BibTeX: @article{glamazda2021, author = {Glamazda, A. Yu. and Gnezdilov, V. P. and Lemmens, P. and Zvyagina, G. A. and Gudim, I. A.}, title = {Raman scattering study of the rare-earth binary ferroborate Nd_0.75Dy_0.25Fe₃(BO₃)₄ single crystal}, journal = {Low Temperature Physics}, year = {2021}, volume = {47}, number = {12}, pages = {1011-1021}, doi = {http://dx.doi.org/10.1063/10.0007074} }
Salak A.N., Cardoso J.P.V., Vieira J.M., Shvartsman V.V., Khalyavin D.D., Fertman E.L., Fedorchenko A.V., Pushkarev A.V., Radyush Y.V., Olekhnovich N.M., Tarasenko R., Feher A., Čižmár E.	Magnetic behaviour of perovskite compositions derived from BiFeO₃ [Abstract] [BibTeX]	2021	Magnetochemistry Vol. 7(11), pp. 151	DOI
Abstract: The phase content and sequence, the crystal structure, and the magnetic properties of perovskite solid solutions of the (1-y)BiFeO_3-yBiZn_0.5Ti_0.5O₃ series (0.05 ≤ y ≤ 0.90) synthesized under high pressure have been studied. Two perovskite phases, namely the rhombohedral R3c and the tetragonal P4mm, which correspond to the structural types of the end members, BiFeO₃ and BiZn_0.5Ti_0.5O₃, respectively, were revealed in the as-synthesized samples. The rhombohedral and the tetragonal phases were found to coexist in the compositional range of 0.30 ≤ y ≤ 0.90. Magnetic properties of the BiFe_1-y[Zn_0.5Ti_0.5]_yO₃ ceramics with y < 0.30 were measured as a function of temperature. The obtained compositional variations of the normalized unit-cell volume and the Néel temperature of the BiFe_1-y[Zn_0.5Ti_0.5]_yO₃ perovskites in the range of their rhombohedral phase were compared with the respective dependences for the BiFe_1-yB_3+yO₃ perovskites (where B³⁺ = Ga, Co, Mn, Cr, and Sc). The role of the high-pressure synthesis in the formation of the antiferromagnetic states different from the modulated cycloidal one characteristic of the parent BiFeO₃ is discussed.
BibTeX: @article{salak2021, author = {Salak, A. N. and Cardoso, J. P. V. and Vieira, J. M. and Shvartsman, V. V. and Khalyavin, D. D. and Fertman, E. L. and Fedorchenko, A. V. and Pushkarev, A. V. and Radyush, Y. V. and Olekhnovich, N. M. and Tarasenko, R. and Feher, A. and Čižmár, E.}, title = {Magnetic behaviour of perovskite compositions derived from BiFeO₃}, journal = {Magnetochemistry}, year = {2021}, volume = {7}, number = {11}, pages = {151}, doi = {http://dx.doi.org/10.3390/magnetochemistry7110151} }
Panfilov A.S., Grechnev G.E.	Effect of hydrostatic pressure on the magnetic susceptibility of MnF₂ single crystal [Abstract] [BibTeX]	2021	Low Temperature Physics Vol. 47(10), pp. 863-866	DOI
Abstract: For the classical antiferromagnet MnF2 with 𝑇𝑁≃67K, the pressure dependence of static magnetic susceptibility χ at T > TN was studied for the first time. The measurements of χ(P) were carried out at fixed temperatures 78, 140, and 300 K using a pendulum-type magnetometer and helium gas pressure P up to 2 kbar. The experimental data on the pressure derivative of magnetic susceptibility, d lnχ/dP, were analyzed within the Curie–Weiss law for χ(T) behavior, yielding estimate of the pressure derivative of paramagnetic Curie temperature dΘ/dP = – (0.31 ± 0.05) K/kbar and value (1/Θ)dΘ/dP = (3.5 ± 0.5) Mbar–1. The obtained experimental result is explained by the volume dependence of superexchange interaction between the magnetic moments of Mn2+ ions.
BibTeX: @article{panfilov2021ii, author = {Panfilov, A. S. and Grechnev, G. E.}, title = {Effect of hydrostatic pressure on the magnetic susceptibility of MnF₂ single crystal}, journal = {Low Temperature Physics}, year = {2021}, volume = {47}, number = {10}, pages = {863-866}, doi = {http://dx.doi.org/10.1063/10.0006067} }
Fil V.D., Fil D.V., Zvyagina G.A., Zhekov K.R., Bilych I.V., Chareev D.A., Kolodyazhnaya M.P., Bludov A., Nazarova E.	Piezomagnetism of superconducting iron chalcogenides [Abstract] [BibTeX]	2021	Physical Review B - Condensed Matter and Materials Physics Vol. 104, pp. 094424	DOI
Abstract: Experiments on the acoustoelectric transformation in superconducting compounds based on FeSe reveal the manifestation of piezomagnetism in them. It allows us to refer the family of superconducting chalcogenides to the systems with a hidden magnetic order and broken time-reversal symmetry. The anisotropy of the piezomagnetic response indicates that the crystal structure of these compounds belongs to the trigonal syngony, in the low-temperature phase.
BibTeX: @article{fil2021, author = {Fil, V. D. and Fil, D. V. and Zvyagina, G. A. and Zhekov, K. R. and Bilych, I. V. and Chareev, D. A. and Kolodyazhnaya, M. P. and Bludov, A. and Nazarova, E.}, title = {Piezomagnetism of superconducting iron chalcogenides}, journal = {Physical Review B - Condensed Matter and Materials Physics}, publisher = {American Physical Society}, year = {2021}, volume = {104}, pages = {094424}, doi = {http://dx.doi.org/10.1103/PhysRevB.104.094424} }
Feodosyev S., Gospodarev I., Syrkin E., Sirenko V., Bondar I., Minakova K.	Peculiar features of vibrations propagation and localization in graphene nanostructures [Abstract] [BibTeX]	2021	2021 IEEE 2nd KhPI Week on Advanced Technology (KhPIWeek), pp. 676-680	DOI
Abstract: The nature of flexural rigidity of graphene monolayers and a formation of the quasiflexural modes in a graphite and the graphene nanofilms is explained. It is shown, that in the major part of the band of quasicontinuous spectrum, quasiflexural modes do not practically couple with the modes polarized in the plane of the layer. The frequencies of propagone zone are determined for the phonons with various polarizations. The existence of high-frequency propagation zone is demonstrated for quasi-flexural phonons. The conditions for a formation of quasi-local vibrations and boson peaks are analyzed for modes with different polarization. The conditions for the formation of quasi-local vibrations and boson peaks in modes of different polarization are analyzed.
BibTeX: @conference{feodosyev2021c, author = {Feodosyev, S. and Gospodarev, I. and Syrkin, E. and Sirenko, V. and Bondar, I. and Minakova, K.}, title = {Peculiar features of vibrations propagation and localization in graphene nanostructures}, journal = {2021 IEEE 2nd KhPI Week on Advanced Technology (KhPIWeek)}, year = {2021}, pages = {676-680}, doi = {http://dx.doi.org/10.1109/KhPIWeek53812.2021.9570040} }
Vieira D.E.L., Cardoso J.P.V., Fedorchenko A.V., Fertman E.L., Čižmár E., Feher A., Babkin R.Y., Pashkevich Y.G., Brett C., Vieira J.M., Salak A.	Magnetic-field-assisted deposition of self-assembling crystallite layers of Co²⁺-containing layered double hydroxides [Abstract] [BibTeX]	2021	Chemical Communications Vol. 57, pp. 6899-6902	DOI
Abstract: Precipitation of nanocrystallites of cobalt-aluminium layered double hydroxides in a magnetic field has been studied. In a magnetic field perpendicular to the substrate, dense and homogeneous films have been obtained. Magnetic anisotropy of the crystallites is explained by deviation from the statistical cation distribution in favour of honeycomb-like coordination of cobalt.
BibTeX: @article{vieira2021, author = {Vieira, D. E. L. and Cardoso, J. P. V. and Fedorchenko, A. V. and Fertman, E. L. and Čižmár, E. and Feher, A. and Babkin, R. Y. and Pashkevich, Y. G. and Brett, C. and Vieira, J. M. and Salak, A.}, title = {Magnetic-field-assisted deposition of self-assembling crystallite layers of Co²⁺-containing layered double hydroxides}, journal = {Chemical Communications}, publisher = {The Royal Society of Chemistry}, year = {2021}, volume = {57}, pages = {6899-6902}, doi = {http://dx.doi.org/10.1039/D1CC01599K} }
Panfilov A.S., Grechnev G.E., Lyogenkaya A.A., Pashchenko V.A., Vasylechko L.O., Hreb V.M., Kovalevsky A.V.	Magnetic and structural properties of La_1-xGd_xCoO₃ compounds [Abstract] [BibTeX]	2021	Physica B: Condensed Matter Vol. 609, pp. 412848	DOI
Abstract: We present a study of magnetic and structural properties of La_1-xGd_xCoO₃ compounds with x=0, 0.2, 0.5 and 1. The Gd term in magnetic susceptibility obeys the Curie-Weiss law with antiferromagnetic interaction between the magnetic moments of Gd³⁺ ions. The value of the paramagnetic Curie temperature Θ is proportional to Gd content and for GdCoO₃ it reaches Θ≃-5.5 K. The Co contribution, χCo(T), derived by subtracting the Gd term from the total susceptibility, shows a non-monotonous behavior which is originated by the temperature induced transition of Co³⁺ ions from the ground low spin state to a higher spin state separated by an energy Δ. The revealed strong increase in Δ with increasing Gd content is presumably due to the manifestation of a chemical pressure upon replacing La with Gd having a smaller ionic size.
BibTeX: @article{panfilov2021, author = {Panfilov, A. S. and Grechnev, G. E. and Lyogenkaya, A. A. and Pashchenko, V. A. and Vasylechko, L. O. and Hreb, V. M. and Kovalevsky, A. V.}, title = {Magnetic and structural properties of La_1-xGd_xCoO₃ compounds}, journal = {Physica B: Condensed Matter}, year = {2021}, volume = {609}, pages = {412848}, doi = {https://doi.org/10.1016/j.physb.2021.412848} }
Zvyagin A.A., Zvyagina G.A.	Piezoelectric and magneto-elastic effects in a quantum paramagnet [Abstract] [BibTeX]	2021	Low Temperature Physics Vol. 47(2), pp. 123-129	DOI
Abstract: Electric, piezoelectric, and elastic characteristics of the orthorhombic quantum paramagnet are calculated. Using the exact analytical solution it was shown that the electric permittivity, piezoelectric, and elastic modules can manifest strong dependences on the values of the external magnetic, electric field, external strain, and temperature.
BibTeX: @article{zvyagin2021, author = {Zvyagin, A. A. and Zvyagina, G. A.}, title = {Piezoelectric and magneto-elastic effects in a quantum paramagnet}, journal = {Low Temperature Physics}, year = {2021}, volume = {47}, number = {2}, pages = {123-129}, doi = {http://dx.doi.org/10.1063/10.0003173} }
Feodosyev S.B., Sirenko V.A., Gospodarev I.A., Bondar I.S., Syrkin E.S., Minakova K.A.	Vibrational characteristics of graphene nanostructures: stability, low-dimensional peculiarities and peculiarities of phonon expansion and localization [Abstract] [BibTeX]	2020	2020 IEEE KhPI Week on Advanced Technology (KhPIWeek), pp. 482-487	DOI
Abstract: Among the large number of both fundamental and ordinary studies of various physical parts of nanomaterials, the study of graphene structures, such as nanofilms (bigraphene, trigraphene) and nanotubes is undoubtedly a priority. At first sight, from a practical point of view, the vibrational characteristics of these structures do not seem to be as relevant as the spectra of some of the other quasiparticle excitations and their properties (e.g., electronic and magnetic), this is clearly not the case. First of all, the phonon spectrum determines the stability of the structure, which is especially important for the building of nanostructures. Secondly, some properties that are manifested by investigated nanoobjects, or those that are already being applied and are currently being put into effect, or those that are still in demand (such as increased conductivity of graphene structures), manifest themselves with a significant and even decisive participation of phonons. One more thought is the theoretical background of the dynamic stability of carbon nanostructures, which is very important for "fine tuning" the process of their synthesis and determining the operating conditions of devices based on this structures. In addition, an analysis of the rms amplitudes of atomic displacements makes it real to define the limits of applicability of the harmonic approximation when considering vibrations of graphite and bigraphene, trigraphene, i.e., the use of phonons and phonons modes to explain heat capacity, root-mean-square (rms) atomic displacements, thermal expansion of the concepts themselves, which is not a priori obvious.
BibTeX: @conference{feodosyev2020, author = {Feodosyev, S. B. and Sirenko, V. A. and Gospodarev, I. A. and Bondar, I. S. and Syrkin, E. S. and Minakova, K. A.}, title = {Vibrational characteristics of graphene nanostructures: stability, low-dimensional peculiarities and peculiarities of phonon expansion and localization}, journal = {2020 IEEE KhPI Week on Advanced Technology (KhPIWeek)}, year = {2020}, pages = {482-487}, doi = {http://dx.doi.org/10.1109/KhPIWeek51551.2020.9250081} }
Fertman E.L., Fedorchenko A.V., Čižmár E., Vorobiov S., Feher A., Radyush Y.V., Pushkarev A.V., Olekhnovich N.M., Stanulis A., Barron A.R., Khalyavin D.D., Salak A.N.	Magnetic diagram of the high-pressure stabilized multiferroic perovskites of the BiFe_1-ySc_yO₃ series [Abstract] [BibTeX]	2020	Crystals Vol. 10(10), pp. 950	DOI
Abstract: Magnetic properties of the high-pressure stabilized perovskite BiFe_1-ySc_yO₃ phases (0.1 ≤ y ≤ 0.9) have been studied by means of magnetization measurements and neutron diffraction. The metastable perovskites of this series undergo irreversible polymorphic transformations upon annealing, the phenomenon referred to as conversion polymorphism. It has been found that the solid solutions with y ≥ 0.70 exhibit no long-range magnetic ordering regardless of their polymorph modification, while those with y ≤ 0.60 are all antiferromagnets. Depending on the scandium content, temperature and structural distortions, three types of the antiferromagnetic orderings, involving collinear, canted and cycloidal spin arrangements, have been revealed in the phases obtained via conversion polymorphism and the corresponding magnetic phase diagram has been suggested.
BibTeX: @article{fertman2020ii, author = {Fertman, E. L. and Fedorchenko, A. V. and Čižmár, E. and Vorobiov, S. and Feher, A. and Radyush, Y. V. and Pushkarev, A. V. and Olekhnovich, N. M. and Stanulis, A. and Barron, A. R. and Khalyavin, D. D. and Salak, A. N.}, title = {Magnetic diagram of the high-pressure stabilized multiferroic perovskites of the BiFe_1-ySc_yO₃ series}, journal = {Crystals}, year = {2020}, volume = {10}, number = {10}, pages = {950}, doi = {http://dx.doi.org/10.3390/cryst10100950} }
Bilych I.V., Kolodyazhnaya M.P., Zhekov K.R., Zvyagina G.A., Fil V.D., Gudim I.A.	Elastic, magnetoelastic, magnetopiezoelectric, and magnetodielectric characteristics of HoAl₃(BO₃)₄ [Abstract] [BibTeX]	2020	Low Temperature Physics Vol. 46(9), pp. 923-931	DOI
Abstract: The main elastic moduli and piezoelectric modulus have been measured in holmium alumoborate single crystals. The renormalization of the permittivity, piezoresponse, and sound velocities, driven by the nematic-like paramagnetic phase in the sample, is considered. A significant variability of the results is detected, which is caused, presumably, by the fact that, under the action of external fields, the motion trajectory of the nematic-like phase’s director depends on random defects of thermoelastic origin. It is shown that above 5 K, the temperature dependences of the studied parameters are well-described using holmium ion’s known ground multiplet spectrum, formed by the interaction with the crystal field. Changes in the C44-mode velocity in the sub-Kelvin temperature range are measured.
BibTeX: @article{bilych2020, author = {Bilych, I. V. and Kolodyazhnaya, M. P. and Zhekov, K. R. and Zvyagina, G. A. and Fil, V. D. and Gudim, I. A.}, title = {Elastic, magnetoelastic, magnetopiezoelectric, and magnetodielectric characteristics of HoAl₃(BO₃)₄}, journal = {Low Temperature Physics}, year = {2020}, volume = {46}, number = {9}, pages = {923-931}, doi = {http://dx.doi.org/10.1063/10.0001715} }
Andreev A.V., Gorbunov D.I., Nomura T., Zvyagin A.A., Zvyagina G.A., Zherlitsyn S.	High-field magnetoacoustics of a Dy₂Fe₁₄Si₃ single crystal [Abstract] [BibTeX]	2020	Journal of Alloys and Compounds Vol. 835, pp. 155335	DOI
Abstract: Dy2Fe14Si3 (hexagonal crystal structure of the Th2Ni17 type) is a highly-anisotropic ferrimagnet with spontaneous magnetic moment Ms = 8 uB per formula unit (at 2 K), directed along the Fe sublattice, and Curie temperature TC = 500 K. The magnetic anisotropy is of the easy-plane type with the [100] axis as an easy magnetization direction. Large anisotropy is observed also within the basal plane. In fields applied along the [100] and [120] axes, field-induced phase transitions were observed at 33 T (of the first order) and at 41 T (of the second order), respectively (at 2 K). Relative changes of sound velocity and changes of sound attenuation at these phase transitions in a Dy2Fe14Si3 single crystal were measured in pulsed magnetic fields up to 58 T at 2 K and elevated temperatures. The performed theoretical analysis suggests that the interaction of the elastic subsystem with the magnetic one is of the exchange-striction nature.
BibTeX: @article{andreev2020, author = {Andreev, A. V. and Gorbunov, D. I. and Nomura, T. and Zvyagin, A. A. and Zvyagina, G. A. and Zherlitsyn, S.}, title = {High-field magnetoacoustics of a Dy₂Fe₁₄Si₃ single crystal}, journal = {Journal of Alloys and Compounds}, year = {2020}, volume = {835}, pages = {155335}, doi = {https://doi.org/10.1016/j.jallcom.2020.155335} }
Panfilov A.S., Lyogenkaya A.A., Grechnev G.E., Pashchenko V.A., Vasylechko L.O., Hreb V.M., Kovalevsky A.V.	Effects of temperature and pressure on the magnetic properties of La_1-xPr_xCoO₃ [Abstract] [BibTeX]	2020	Physica Satus Solidi (b) Vol. 257(9), pp. 2000085	DOI
Abstract: For La_1-xPr_xCoO₃ cobaltites (x=0, 0.1, 0.2, and 0.3), the dependence of magnetic susceptibility X(T) is studied in the temperature range 5-400 K. Also, the crystal structure of these cobaltites is investigated, and the effect of pressure up to 2 kbar on their susceptibility is measured at T=78, 150, and 300 K. The specific dependencies X(T) and the large negative pressure effect are assumed to arise from Co3+ ions contribution to the total susceptibility evaluated using La_1-xPr_xAlO₃ as a reference system. The obtained experimental data on temperature and pressure effects in magnetism are analyzed within a two-level model with energy gap Delta between the ground state of the system with zero spin of Co3+ ions and the excited higher-spin state. In this model, magnetism of Co3+ ions is determined by the temperature-induced population of the excited state, and magnitude of the pressure effect is governed by the volume dependence of Delta. The results of the analysis, supplemented by the theoretical calculations of the electronic structures of LaCoO3 and PrCoO3, indicate significant increase in Delta with decrease in the unit cell volume both under hydrostatic pressure and by substituting La with Pr having a smaller ionic radius.
BibTeX: @article{panfilov2020ii, author = {Panfilov, A. S. and Lyogenkaya, A. A. and Grechnev, G. E. and Pashchenko, V. A. and Vasylechko, L. O. and Hreb, V. M. and Kovalevsky, A. V.}, title = {Effects of temperature and pressure on the magnetic properties of La_1-xPr_xCoO₃}, journal = {Physica Satus Solidi (b)}, year = {2020}, volume = {257}, number = {9}, pages = {2000085}, doi = {http://dx.doi.org/10.1002/pssb.202000085} }
Cardoso J.P., Delmonte D., Gilioli E., Fertman E.L., Fedorchenko A.V., Shvartsman V.V., Paukšta V., Grigalaitis R., Banys J., Khalyavin D.D., Vieira J.M., Salak A.N.	Phase transitions in the metastable perovskite multiferroics BiCrO₃ and BiCr_0.9Sc_0.1O₃: a comparative study [Abstract] [BibTeX]	2020	Inorganic Chemistry Vol. 59(13), pp. 8727-8735	DOI
Abstract: The temperature behavior of the crystal structure as well as dielectric and magnetic properties of the perovskite bismuth chromate ceramics with the 10 mol % Cr3+-to-Sc3+ substitution were studied and compared with those of the unmodified compound. Using a high-pressure synthesis, BiCrO3 and BiCr0.9Sc0.1O3 were obtained as metastable perovskite phases which are monoclinic C2/c with the √6ap × √2ap × √6ap superstructure (where ap is the primitive perovskite unit-cell parameter) under ambient conditions. At room temperature, the unit cell volume of BiCr0.9Sc0.1O3 is ∼1.3% larger than that of BiCrO3. Both perovskites undergo a reversible structural transition into a nonpolar GdFeO3-type phase (orthorhombic Pnma, √2ap × 2ap × √2ap) in the temperature ranges of 410–420 K (BiCrO3) and 470–520 K (BiCr0.9Sc0.1O3) with a relative jump of the primitive perovskite unit cell volume of about −1.6 and −2.0 respectively. Temperature dependences of the complex dielectric permittivity demonstrate anomalies in the phase transition ranges. The Pnma-to-C2/c crossover in BiCrO3 is accompanied by a decrease in the direct current (dc) conductivity, while in BiCr0.9Sc0.1O3 the conductivity increases. The onset of an antiferromagnetic order in BiCr0.9Sc0.1O3 is observed at the Néel temperature (TN) of about 85 K as compared with TN = 110 K in BiCrO3. In contrast to BiCrO3, which exhibits a spin reorientation at Tsr ∼ 72 K, no such a transition occurs in BiCr0.9Sc0.1O3.
BibTeX: @article{cardoso2020, author = {Cardoso, J. P. and Delmonte, D. and Gilioli, E. and Fertman, E. L. and Fedorchenko, A. V. and Shvartsman, V. V. and Paukšta, V. and Grigalaitis, R. and Banys, J. and Khalyavin, D. D. and Vieira, J. M. and Salak, A. N.}, title = {Phase transitions in the metastable perovskite multiferroics BiCrO₃ and BiCr_0.9Sc_0.1O₃: a comparative study}, journal = {Inorganic Chemistry}, year = {2020}, volume = {59}, number = {13}, pages = {8727-8735}, doi = {http://dx.doi.org/10.1021/acs.inorgchem.0c00338} }
Panfilov A.S., Lyogenkaya A.A., Grechnev G.E., Pashchenko V.A., Vasylechko L.O., Hreb V.M., Kovalevsky A.V.	The effect of temperature and pressure on the spin state of cobalt ions in La_1-xPr_xCoO₃ compounds [Abstract] [BibTeX]	2020	Low Temperature Physics Vol. 46(6), pp. 606-614	DOI
Abstract: The crystal structure, magnetic susceptibility as a function of temperature chi(T) in the range 5-400 K, and the hydrostatic pressure effect on chi at fixed temperaturesT = 78, 150, and 300 K, were studied in perovskite-like compounds La1-xPrxCoO3(x = 0, 0.1, 0.2, and 0.3). The obtained experimental data were analyzed using a two-level model with an energy gap Delta between the ground and excited states of the system that correspond to the spin valuesS = 0 and 1 for Co(3+)ions. In this model, the magnetism of Co(3+)ions, which determines the features of the chi (T) dependence, is ensured by the temperature-induced change in the population of the excited state. The anomalously large magnitude of the observed pressure effect is associated with the high sensitivity of Delta to changes in the lattice volume, under the influence of both hydrostatic and chemical pressures, when La is replaced by the smaller Pr ion in the considered system. Theoretical calculations of the electronic structure for the boundary compounds LaCoO(3)and PrCoO(3)confirm the significant increase in the excitation energy Delta with a decrease in the lattice volume, and also support the scenario of a spin crossover between the states of cobalt ions with low and intermediate spin values.
BibTeX: @article{panfilov2020, author = {Panfilov, A. S. and Lyogenkaya, A. A. and Grechnev, G. E. and Pashchenko, V. A. and Vasylechko, L. O. and Hreb, V. M. and Kovalevsky, A. V.}, title = {The effect of temperature and pressure on the spin state of cobalt ions in La_1-xPr_xCoO₃ compounds}, journal = {Low Temperature Physics}, year = {2020}, volume = {46}, number = {6}, pages = {606-614}, doi = {http://dx.doi.org/10.1063/10.0001244} }
Romaka V.V., Prikhna T.A., Eisterer M., Shapovalov A.P., Goldacker W., Moshchil V.E., Kozyrev A., Rindfleisch M., Tompsic M., Hellstrom E.E., Grechnev G.E., Zhang V.S., Yang F., Li C.	Structure and properties of MgB₂ bulks: ab-initio simulations compared to experiment [Abstract] [BibTeX]	2020	IOP Conference Series: Materials Science and Engineering Vol. 756, pp. 012020	DOI
Abstract: Analysis of XRD patterns by Rietveld refinement has been shown that the main phase of superconducting MgB2-based bulk materials (with high level of superconducting characteristics) has AlB2 type structure and near MgB1.8-1.68O0.2-0.32 stoichiometry. The materials demonstrated the critical current densities up to 0.9 – 0.4 MA/cm2 j c (at 0 - 1 T, 20 K); up to 15 T B c2 (at 22.5 K) and Birr (at 18 K). The ab-initio simulation confirmed (1) benefits in binding energy and enthalpy of formation if stoichiometry of the solid solution is near MgB1.75O0.25; (2) energetic advantage in case if impurity oxygen present only in each second boron plane of MgB2 cell while the first boron plane of the same cell stays pristine and location of substituted oxygen atoms in the nearby positions. Besides, the results of ab-initio modeling allow explanation of the tendency towards segregation of O-impurity in MgB2 structure during synthesis or sintering, and formation of Mg-B-O inclusions or nanolayers (with MgO type of structure) which effect pinning. Calculated transition temperatures, Tc, for MgB1.75O0.25 occurred to be 23.3 K, while for MgB2 it was 21.13 K only. Experimental Tc of the bulk materials was 35.7-38.2 K.
BibTeX: @article{Romaka_2020, author = {Romaka, V. V. and Prikhna, T. A. and Eisterer, M. and Shapovalov, A. P. and Goldacker, W. and Moshchil, V. E. and Kozyrev, A. and Rindfleisch, M. and Tompsic, M. and Hellstrom, E. E. and Grechnev, G. E. and Zhang, V. Sh and Yang, F. and Li, Ch}, title = {Structure and properties of MgB₂ bulks: ab-initio simulations compared to experiment}, journal = {IOP Conference Series: Materials Science and Engineering}, publisher = {IOP Publishing}, year = {2020}, volume = {756}, pages = {012020}, doi = {http://dx.doi.org/10.1088/1757-899x/756/1/012020} }
Fertman E.L., Fedorchenko A.V., Desnenko V.A., Shvartsman V.V., Lupascu D.C., Salamon S., Wende H., Vaisburd A.I., Stanulis A., Ramanauskas R., Olekhnovich N.M., Pushkarev A.V., Radyush Y.V., Khalyavin D.D., Salak A.N.	Exchange bias effect in bulk multiferroic BiFe_0.5Sc_0.5O₃ [Abstract] [BibTeX]	2020	AIP Advances Vol. 10(4), pp. 045102	DOI
Abstract: Below the Néel temperature, T_N∼220 K, at least two nano-scale antiferromagnetic (AFM) phases coexist in the polar polymorph of the BiFe_0.5Sc_0.5O₃ perovskite; one of these phases is a weak ferromagnetic. Non-uniform structure distortions induced by high-pressure synthesis lead to competing AFM orders and a nano-scale spontaneous magnetic phase separated state of the compound. Interface exchange coupling between the AFM domains and the weak ferromagnetic domains causes unidirectional anisotropy of magnetization, resulting in the exchange bias (EB) effect. The EB field, H_EB , and the coercive field strongly depend on temperature and the strength of the cooling magnetic field. H_EB increases with an increase in the cooling magnetic field and reaches a maximum value of about 1 kOe at 5 K. The exchange field vanishes above T_N with the disappearance of long-range magnetic ordering. The effect is promising for applications in electronics as it is large enough and as it is tunable by temperature and the magnetic field applied during cooling.
BibTeX: @article{fertman2020, author = {Fertman, E. L. and Fedorchenko, A. V. and Desnenko, V. A. and Shvartsman, V. V. and Lupascu, D. C. and Salamon, S. and Wende, H. and Vaisburd, A. I. and Stanulis, A. and Ramanauskas, R. and Olekhnovich, N. M. and Pushkarev, A. V. and Radyush, Yu. V. and Khalyavin, D. D. and Salak, A. N.}, title = {Exchange bias effect in bulk multiferroic BiFe_0.5Sc_0.5O₃}, journal = {AIP Advances}, year = {2020}, volume = {10}, number = {4}, pages = {045102}, doi = {http://dx.doi.org/10.1063/1.5135586} }
Lukienko I.N., Kharchenko M.F., Fedorchenko A.V., Kharlan I.A., Tutakina O.P., Stetsenko O.N., Neves C.S., Salak A.N.	Faraday effect and fragmentation of ferromagnetic layers in multilayer Co/Cu(1 1 1) nanofilms [Abstract] [BibTeX]	2020	Journal of Magnetism and Magnetic Materials Vol. 505, pp. 166706	DOI
Abstract: With purpose to investigate influence of magnetically non-active metal layers on the Faraday effect in multilayer Ferromagnetic/Normal metal films, dependences of the Faraday rotation angles of the light polarization plane on magnetic field have been studied in multilayer [Co/Cu] nanofilms. It was revealed that the Faraday rotation φ varies with thickness of the Cu layers dCu. This φ(dCu) dependence consists of the monotonic component, namely a gradual rise of the angle with increase of dCu, and the non-monotonic one represented by two minima. The monotonic changes of the Faraday rotation were satisfactory described in frames of the effective medium method. Two minima are explained with the Co layer’s fragmentation due to influence of size electron quantization in the Cu layers on formation of Co clusters during deposition of the films.
BibTeX: @article{lukienko2020, author = {Lukienko, I. N. and Kharchenko, M. F. and Fedorchenko, A. V. and Kharlan, I. A. and Tutakina, O. P. and Stetsenko, O. N. and Neves, C. S. and Salak, A. N.}, title = {Faraday effect and fragmentation of ferromagnetic layers in multilayer Co/Cu(1 1 1) nanofilms}, journal = {Journal of Magnetism and Magnetic Materials}, year = {2020}, volume = {505}, pages = {166706}, doi = {https://doi.org/10.1016/j.jmmm.2020.166706} }
Gospodarev I.A., Sirenko V.A., Syrkin E.S., Feodosyev S.B., Minakova K.A.	Low dimensional features of graphene nanostructure stability and vibrational characteristics (Review) [Abstract] [BibTeX]	2020	Low Temperature Physics Vol. 46(3), pp. 232-257	DOI
Abstract: The densities of phonon states and their related vibrational thermodynamic characteristics, such as heat capacity, root-mean-square displacement of atoms, and thermal expansion, are calculated and analyzed at the microscopic level for graphite and graphene nanoformations, such as nanofilms and nanotubes. The simulation model is based on experimental data without a priori assumptions as to the nature and potentials of interatomic interactions, and is compared to them only after, which yields a good agreement. The quasi-flexural and torsional modes, which are inherent to graphene nanotubes, are considered and their contribution to the low temperature vibrational characteristics are analyzed. The impact that extended defects, such as graphite intercalation with transition metals, step-edges on graphene nanofilms, and edges of a graphene single layer on a substrate, have on the phonon spectrum and vibrational characteristics is analyzed. The calculated results are compared to the experimental data.
BibTeX: @article{gospodarev2020ii, author = {Gospodarev, I. A. and Sirenko, V. A. and Syrkin, E. S. and Feodosyev, S. B. and Minakova, K. A.}, title = {Low dimensional features of graphene nanostructure stability and vibrational characteristics (Review)}, journal = {Low Temperature Physics}, year = {2020}, volume = {46}, number = {3}, pages = {232-257}, doi = {http://dx.doi.org/10.1063/10.0000706} }
Gospodarev I.A., Grishaev V.I., Manzhelii E.V., Sirenko V.A., Syrkin E.S., Feodosyev S.B.	The effect of size quantization on the electron spectra of graphene nanoribbons [Abstract] [BibTeX]	2020	Low Temperature Physics Vol. 46(2), pp. 187-194	DOI
Abstract: The total electron densities of states for graphene nanoribbons with edges of different chirality, as well as the electron local densities of states for individual atoms in these nanoribbons, are calculated and analyzed. There are sharp resonance peaks near the Fermi level in the total electron densities of states of graphene nanoribbons with zigzag edges, which emerge only in the local densities of atoms from the sublattice that goes directly to the nearest edge (i.e., whose atoms have dangling bonds). Semiconducting gaps appear in the spectra of graphene nanobands with armchair chirality edges having a number of constituent atomic lines that is either a multiple of three, or gives a remainder of one when divided by three. The width of this gap only depends on the width of the nanoribbon, and is the same for all its atoms. The electron spectra of graphene nanoribbons with armchair-chirality edges have a metallic behavior if the number of atomic lines gives a remainder of two when divided by three. However, semiconducting gaps still manifest on the local densities of the atoms belonging to some lines of such nanoribbons.
BibTeX: @article{gospodarev2020, author = {Gospodarev, I. A. and Grishaev, V. I. and Manzhelii, E. V. and Sirenko, V. A. and Syrkin, E. S. and Feodosyev, S. B.}, title = {The effect of size quantization on the electron spectra of graphene nanoribbons}, journal = {Low Temperature Physics}, year = {2020}, volume = {46}, number = {2}, pages = {187-194}, doi = {http://dx.doi.org/10.1063/10.0000539} }
Feodosyev S.B., Gospodarev I.A., Manzhelii E.V., Sirenko V.A., Syrkin E.S.	Discrete atomic vibrations localized on defects in linear chains of atoms adsorbed by carbon nanobundles [Abstract] [BibTeX]	2019	Low Temperature Physics Vol. 45(7), pp. 763-768	DOI
Abstract: The conditions of the existence and the main characteristics (frequencies, intensities, and attenuation parameters) of discrete vibrational levels caused by structural defects of linear chains of inert gas atoms adsorbed on the surface of nanotubes aggregated in nanobundles, are calculated and analyzed. Discrete vibrational levels lying both above and below the band of the quasi-continuous spectrum of the chain are considered. Analytical expressions obtained for the frequencies of these discrete levels make it possible to determine with high precision the defect parameters (difference in the interaction with the substrate and with the atoms of the chain) basing on optical measurements.
BibTeX: @article{feodosyev2019, author = {Feodosyev, S. B. and Gospodarev, I. A. and Manzhelii, E. V. and Sirenko, V. A. and Syrkin, E. S.}, title = {Discrete atomic vibrations localized on defects in linear chains of atoms adsorbed by carbon nanobundles}, journal = {Low Temperature Physics}, year = {2019}, volume = {45}, number = {7}, pages = {763-768}, doi = {http://dx.doi.org/10.1063/1.5111304} }
Gorbunov D.I., Nomura T., Zvyagin A.A., Henriques M.S., Andreev A.V., Skourski Y., Zvyagina G.A., Troć R., Zherlitsyn S., Wosnitza J.	Magnetoelastic coupling across the field-induced transition of uranium mononitride [Abstract] [BibTeX]	2019	Physical Review B - Condensed Matter and Materials Physics Vol. 100, pp. 024417	DOI
Abstract: Uranium mononitride (UN) displays a spin-flop-like transition for magnetic field applied along all principal crystallographic directions just below 60 T. Here, we report on ultrasound and magnetocaloric-effect results for UN in pulsed magnetic fields up to 65 T. The field-induced phase transition causes a discontinuous temperature decrease, indicating a larger magnetic entropy above the transition. Furthermore, we find pronounced anomalies in the acoustic properties, which signals strong spin-lattice interactions. A further anomaly observed at fields slightly above the transition is likely related to the formation of magnetic domains. A model based on the exchange-striction coupling mechanism well reproduces the strong renormalization of the acoustic properties.
BibTeX: @article{gorbunov2019, author = {Gorbunov, D. I. and Nomura, T. and Zvyagin, A. A. and Henriques, M. S. and Andreev, A. V. and Skourski, Y. and Zvyagina, G. A. and Troć, R. and Zherlitsyn, S. and Wosnitza, J.}, title = {Magnetoelastic coupling across the field-induced transition of uranium mononitride}, journal = {Physical Review B - Condensed Matter and Materials Physics}, publisher = {American Physical Society}, year = {2019}, volume = {100}, pages = {024417}, doi = {http://dx.doi.org/10.1103/PhysRevB.100.024417} }
Zvyagin A.A., Zvyagina G.A.	Spontaneous spin-nematic ordering in a spin-chain system [Abstract] [BibTeX]	2019	Physical Review B - Condensed Matter and Materials Physics Vol. 100, pp. 014416	DOI
Abstract: The spontaneous onset of the spin-nematic order in spin-chain systems is studied. The ordering persists due to distortions of either magnetic ions, or ligands taking part in the superexchange between magnetic ions. The spin-nematic order yields a nonzero biaxial magnetic anisotropy for the spin chain, violating the U(1) symmetry. The influence of the external magnetic field and nonzero temperature is considered. We predict how the spin-nematic ordering can manifest itself in the temperature and magnetic field behavior of magnetoacoustic characteristics.
BibTeX: @article{zvyagin2019, author = {Zvyagin, A. A. and Zvyagina, G. A.}, title = {Spontaneous spin-nematic ordering in a spin-chain system}, journal = {Physical Review B - Condensed Matter and Materials Physics}, publisher = {American Physical Society}, year = {2019}, volume = {100}, pages = {014416}, doi = {http://dx.doi.org/10.1103/PhysRevB.100.014416} }
Salak A.N., Vieira D.E.L., Lukienko I.M., Shapovalov Y.O., Fedorchenko A.V., Fertman E.L., Pashkevich Y.G., Babkin R.Y., Shilin A.D., Rubanik V.V., Ferreira M.G.S., Vieira J.M.	High-power ultrasonic synthesis and magnetic-field-assisted arrangement of nanosized crystallites of cobalt-containing layered double hydroxides [Abstract] [BibTeX]	2019	ChemEngineering Vol. 3(3), pp. 62	DOI
Abstract: High-quality stoichiometric Co₂Al-NO₃ and Co₂Al-CO₃ layered double hydroxides (LDHs) have been obtained by precipitation followed by anion exchange, both high-power-sonication assisted. Application of high-power ultrasound has been demonstrated to result in a considerable acceleration of the crystallization process and the anion-exchange reaction. Two independent approaches were used to form bulk and 2-D samples of Co₂Al-NO₃ with the oriented crystallites, namely uniaxial pressing of deposits from sonicated LDH slurries and magnetic field-assisted arrangement of LDH crystallites precipitating on glass substrates. A convenient way of preparation of semi-transparent compacts with relatively big blocks of oriented crystallites have been demonstrated. Thin dense transparent films of highly-ordered crystallites of Co₂Al-NO₃ LDH have been produced and characterized.
BibTeX: @article{salak2019, author = {Salak, A. N. and Vieira, D. E. L. and Lukienko, I. M. and Shapovalov, Y. O. and Fedorchenko, A. V. and Fertman, E. L. and Pashkevich, Y. G. and Babkin, R. Yu. and Shilin, A. D. and Rubanik, V. V. and Ferreira, M. G. S. and Vieira, J. M.}, title = {High-power ultrasonic synthesis and magnetic-field-assisted arrangement of nanosized crystallites of cobalt-containing layered double hydroxides}, journal = {ChemEngineering}, year = {2019}, volume = {3}, number = {3}, pages = {62}, doi = {http://dx.doi.org/10.3390/chemengineering3030062} }
Khalyavin D.D., Salak A.N., Fertman E.L., Kotlyar O.V., Eardley E., Olekhnovich N.M., Pushkarev A.V., Radyush Y.V., Fedorchenko A.V., Desnenko V.A., Manuel P., Ding L., Čižmár E., Feher A.	The phenomenon of conversion polymorphism in Bi-containing metastable perovskites [Abstract] [BibTeX]	2019	Chemical Communications Vol. 55(32), pp. 4683-4686	DOI
Abstract: A post-synthesis thermal treatment of metastable phases in the high-pressure stabilised perovskite BiFe_1-ySc_yO₃ system results in the irreversible formation of polymorphs which represent novel polar and antipolar structures with interesting magnetic properties. Such annealing-stimulated polymorphism is believed to be a general phenomenon which can be found in other systems.
BibTeX: @article{khalyavin2019, author = {Khalyavin, D. D. and Salak, A. N. and Fertman, E. L. and Kotlyar, O. V. and Eardley, E. and Olekhnovich, N. M. and Pushkarev, A. V. and Radyush, Y. V. and Fedorchenko, A. V. and Desnenko, V. A. and Manuel, P. and Ding, L. and Čižmár, E. and Feher, A.}, title = {The phenomenon of conversion polymorphism in Bi-containing metastable perovskites}, journal = {Chemical Communications}, publisher = {The Royal Society of Chemistry}, year = {2019}, volume = {55}, number = {32}, pages = {4683-4686}, doi = {http://dx.doi.org/10.1039/C9CC00472F} }
Babkin R.Y., Pashkevich Y.G., Fedorchenko A.V., Fertman E.L., Desnenko V.A., Prokhvatilov A.I., Galtsov N.N., Vieira D.E.L., Salak A.N.	Impact of temperature dependent octahedra distortions on magnetic properties of Co-containing double layered hydroxides [Abstract] [BibTeX]	2019	Journal of Magnetism and Magnetic Materials Vol. 473, pp. 501-504	DOI
Abstract: Distortions of hydroxide octahedral complexes in the Co^II_nAl^III layered double hydroxides (LDHs) (n = Co^II/Al^III = 2 and 3) were studied as a function of the ratio of divalent-to-trivalent cations and temperature. A method for calculation the magnetic susceptibility of polycrystalline samples taking into account the statistical distribution of divalent and trivalent cations, and their effect on the distortions of the original structure is proposed. It is shown that the presence of a local maximum on the magnetic susceptibility curve of Co_nAl LDHs compounds near T ∼ 160 K is due to freezing of the lattice parameters and, as a consequence, freezing of the tilting fluctuations of the O-H bonds.
BibTeX: @article{babkin2019, author = {Babkin, R. Y. and Pashkevich, Y. G. and Fedorchenko, A. V. and Fertman, E. L. and Desnenko, V. A. and Prokhvatilov, A. I. and Galtsov, N. N. and Vieira, D. E. L. and Salak, A. N.}, title = {Impact of temperature dependent octahedra distortions on magnetic properties of Co-containing double layered hydroxides}, journal = {Journal of Magnetism and Magnetic Materials}, year = {2019}, volume = {473}, pages = {501-504}, doi = {http://dx.doi.org/10.1016/j.jmmm.2018.10.077} }
Panfilov A.S., Grechnev G.E., Lyogenkaya A.A., Pashchenko V.A., Zhuravleva I.P., Vasylechko L.O., Hreb V.M., Turchenko V.A., Novoselov D.	Magnetic properties of RCoO₃ cobaltites (R = La, Pr, Nd, Sm, Eu). Effects of hydrostatic and chemical pressure [Abstract] [BibTeX]	2019	Physica B: Condensed Matter Vol. 553, pp. 80-87	DOI
Abstract: We have investigated the temperature dependence of the magnetic susceptibility χ(T) of rare-earth cobaltites RCoO₃ (R = La, Pr, Nd, Sm, Eu) in the temperature range 4.2-300 K and also the influence of hydrostatic pressure up to 2 kbar on their susceptibility at fixed temperatures T = 78 and 300 K. The specific dependence χ(T) observed in LaCoO₃ and the anomalously large pressure effect (dlnχ/dP ∼ -100 Mbar^-1 for T = 78 K) are analyzed in the framework of a two-level model with energy levels difference Δ. The ground state of the system is assumed to be nonmagnetic with the zero spin of Co³⁺ ions, and magnetism at a finite temperature is determined by the excited magnetic spin state. The results of the analysis, supplemented by theoretical calculations of the electronic structure of LaCoO₃, indicate a significant increase in Δ with a decrease in the unit cell volume under the hydrostatic pressure. In the series of RCoO₃ (R = Pr, Nd, Sm, Eu) compounds, the volume of crystal cell decreases monotonically due to a decrease in the radius of R³⁺ ions. This leads to an increase in the relative energy Δ of the excited state (the chemical pressure effect), which manifests itself in a decrease in the contribution of cobalt ions to the magnetic susceptibility at a fixed temperature, and also in a decrease in the hydrostatic pressure effect on the susceptibility of RCoO₃ compounds, which we have observed at T = 300 K.
BibTeX: @article{panfilov2019, author = {Panfilov, A. S. and Grechnev, G. E. and Lyogenkaya, A. A. and Pashchenko, V. A. and Zhuravleva, I. P. and Vasylechko, L. O. and Hreb, V. M. and Turchenko, V. A. and Novoselov, D.}, title = {Magnetic properties of RCoO₃ cobaltites (R = La, Pr, Nd, Sm, Eu). Effects of hydrostatic and chemical pressure}, journal = {Physica B: Condensed Matter}, year = {2019}, volume = {553}, pages = {80-87}, doi = {http://dx.doi.org/10.1016/j.physb.2018.10.036} }
Kolodyazhnaya M.P., Zvyagina G.A., Bilych I.V., Zhekov K.P., Burma N.G., Fil V.D., Gudim I.A.	Magnetocapacitance, magnetoelasticity, and magnetopiezoelectric effect in HoFe₃(BO₃)₄ [Abstract] [BibTeX]	2018	Low Temperature Physics Vol. 44(12), pp. 1341-1347	DOI
Abstract: The main components of the tensor of the moduli of elasticity and the piezomodulus have been measured in monocrystals of the ferroborate HoFe3(BO3)4. The spin-dependent contributions to sound velocity, dielectric permeability, and piezoelectric response in the antiferromagnetic state were studied. The parameters of magnetoelectric and magnetoelastic interactions in an easy-plane magnetic-ordering phase have been defined. A phenomenological interpretation of observed effects is given.
BibTeX: @article{Kolodyazhnaya20181341, author = {Kolodyazhnaya, M. P. and Zvyagina, G. A. and Bilych, I. V. and Zhekov, K. P. and Burma, N. G. and Fil, V. D. and Gudim, I. A.}, title = {Magnetocapacitance, magnetoelasticity, and magnetopiezoelectric effect in HoFe₃(BO₃)₄}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2018}, volume = {44}, number = {12}, pages = {1341-1347}, doi = {http://dx.doi.org/10.1063/1.5078631} }
Desnenko V.A., Sirenko V.A., Troyanchuk I.O., Fedorchenko A.V., Yeremenko A.V.	Low-temperature relaxation of magnetization in manganite Pr_0.4Bi_0.3Ca_0.3MnO₃ [Abstract] [BibTeX]	2018	Low Temperature Physics Vol. 44(9), pp. 962-965	DOI
Abstract: Low-temperature relaxation of magnetization in Pr_0.4Bi_0.3Ca_0.3MnO₃ ceramics was measured after cooling in a magnetic field and aging at temperatures from 5 K to 38 K near the transition temperature to the magnetically ordered state. It was found that the relaxation process has a thermoactivation character at the first stage and is described in terms of the Arrhenius equation. Its activation energy Q ≈ 1.1 meV is comparable with the antiferromagnetic interaction energy in this compound. The temperature–time dependence of the relaxation rate at the second stage is described by a power law. The relaxation slows down as the temperature approaches the critical value, which may be associated with the formation of a cluster structure in the studied compound under these conditions.
BibTeX: @article{desnenko2018, author = {Desnenko, V. A. and Sirenko, V. A. and Troyanchuk, I. O. and Fedorchenko, A. V. and Yeremenko, A. V.}, title = {Low-temperature relaxation of magnetization in manganite Pr_0.4Bi_0.3Ca_0.3MnO₃}, journal = {Low Temperature Physics}, year = {2018}, volume = {44}, number = {9}, pages = {962-965}, doi = {http://dx.doi.org/10.1063/1.5052685} }
Čižmár E., Šoltésová D., Kazheva O.N., Alexandrov G.G., Kravchenko A.V., Chekulaeva L.A., Kosenko I.D., Sivaev I.B., Bregadze V.I., Fedorchenko A.V., Starodub V.A., Buravov L.I., Dyachenko O.A., Feher A.	Large magnetic anisotropy of chromium(III) ions in a bis(ethylenedithio)tetrathiafulvalenium salt of chromium bis(dicarbollide), (ET)₂[3,3′-Cr(1,2-C₂B₉H₁₁)₂] [Abstract] [BibTeX]	2018	Transition Metal Chemistry Vol. 43(7), pp. 647-655	DOI
Abstract: The synthesis of a radical-cation salt based on a derivative of tetrathiafulvalene, (ET)2[3,3′-Cr(1,2-C2B9H11)2] (ET = bis(ethylenedithio)tetrathiafulvalenium), was accomplished by electrochemical anodic oxidation of ET in the presence of (Me4N)[3,3´-Cr(1,2-C2B9H11)2] in the galvanostatic regime. An electric conductivity σ (293 K) = 7 × 10−3 Ohm−1 cm−1 with semiconductor activation energy Ea ≅ 0.1 eV in the range of 127–300 K was observed. The crystal structure of (ET)2[3,3′-Cr(1,2-C2B9H11)2] was determined by X-ray diffraction at 173 K, revealing the presence of structural tetramers in radical-cation stacks. The magnetic properties of the complex were investigated in the temperature range 1.8–300 K using magnetometry and EPR, showing that the magnetic structure of (ET)2[3,3′-Cr(1,2-C2B9H11)2] consists of two independent magnetic subsystems. Cation radicals form a rectangular magnetic lattice in the ab-plane with significant antiferromagnetic exchange interactions. The chromium bis(dicarbollide) anions are characterized by unusually strong positive zero-field splitting of the Cr(III) ions, which was confirmed by ab initio calculations.
BibTeX: @article{cizmar2018, author = {Čižmár, E. and Šoltésová, D. and Kazheva, O. N. and Alexandrov, G. G. and Kravchenko, A. V. and Chekulaeva, L. A. and Kosenko, I. D. and Sivaev, I. B. and Bregadze, V. I. and Fedorchenko, A. V. and Starodub, V. A. and Buravov, L. I. and Dyachenko, O. A. and Feher, A.}, title = {Large magnetic anisotropy of chromium(III) ions in a bis(ethylenedithio)tetrathiafulvalenium salt of chromium bis(dicarbollide), (ET)₂[3,3′-Cr(1,2-C₂B₉H₁₁)₂]}, journal = {Transition Metal Chemistry}, year = {2018}, volume = {43}, number = {7}, pages = {647-655}, doi = {http://dx.doi.org/10.1007/s11243-018-0253-1} }
Fedorchenko A.V., Fertman E.L., Salak A.N., Desnenko V.A., Čižmár E., Feher A., Vaisburd A.I., Olekhnovich N.M., Pushkarev A.V., Radyush Y.V., Zarkov A., Kareiva A.	Unusual magnetic properties of the polar orthorhombic BiFe_0.5Sc_0.5O₃ perovskite [Abstract] [BibTeX]	2018	Journal of Magnetism and Magnetic Materials Vol. 465, pp. 328-332	DOI
Abstract: Magnetic properties of new multiferroic BiFe_0.5Sc_0.5O₃ perovskite which exists in two different orthorhombic polymorphs, the antipolar Pnma and the polar Ima2, were studied using a SQUID-magnetometer technique in magnetic fields up to 50 kOe in the temperature range of 5-300 K. Both polymorphs show a weak ferromagnetic component below the Néel temperature, T_N ~220 K. A wide cusp-like anomaly of the temperature dependent magnetic susceptibility was revealed below 200 K. The anomaly is dependent on the magnetic field applied and can be associated with the glassy magnetic behavior of the compound. The best fit of the initial magnetization curves taken at each temperature can be obtained as a sum of two contributions, namely the nonlinear in field and the linear one. The nonlinear contribution appeared to be temperature and magnetic field dependent, which is in a good agreement with the magnetization experimentally obtained as a function of temperature in different magnetic fields applied. Increase of external magnetic field leads to a decrease of the nonlinear contribution to the total magnetic moment.
BibTeX: @article{fedorchenko2018, author = {Fedorchenko, A. V. and Fertman, E. L. and Salak, A. N. and Desnenko, V. A. and Čižmár, E. and Feher, A. and Vaisburd, A. I. and Olekhnovich, N. M. and Pushkarev, A. V. and Radyush, Yu. V. and Zarkov, A. and Kareiva, A.}, title = {Unusual magnetic properties of the polar orthorhombic BiFe_0.5Sc_0.5O₃ perovskite}, journal = {Journal of Magnetism and Magnetic Materials}, year = {2018}, volume = {465}, pages = {328-332}, doi = {http://dx.doi.org/10.1016/j.jmmm.2018.06.015} }
Troyanchuk I., Bushinsky M., Tereshko N., Sirenko V., Sikolenko V., Schorr S., Ritter C., Franz A.	Ferromagnetic ordering, magnetic and magnetotransport properties of R1-xSrx(Mn1-x/2Sbx/2)O3 (R = La, Pr, Nd, Sm, Eu) manganites [Abstract] [BibTeX]	2018	Materials Research Express Vol. 5(6), pp. 066101	DOI
Abstract: Neutron diffraction, magnetic and magnetotransport studies of perovskites R1-x 3+Srx 2+ (Mn1-x 3+ Sbx/ 2 5+ )O3 (R = La, Pr) were carried out. It is shown that for x ∼ 0.2 systems undergo a transition from an antiferromagnetic state (x=0) to a ferromagnetic state. In the case of the R=La series a structural transformation from theO?-orthorhombic phase (x=0) to theO-orthorhombic one occurs, which is due to orbital disordering. At x.0.6 cluster spin glass like phases arise due to the competition between antiferromagnetic and ferromagnetic interactions, as well as due to the strong diamagnetic dilution. In case of the R=Pr series the structural transition into theO-orthorhombic phase was not observed under (Sr, Sb) codoping. As the ionic radius of the rare-earth ion decreases in the series R0.7 Sr0.3 Mn0.85 Sb0.15O3 the crystal structure distortion increases and the ferromagnetic state (R=La, Pr, Nd) is gradually transformed into a spin glass like state (R=Sm, Eu). The ferromagnetic compounds are insulators and exhibit a large magnitude of the magnetoresistance apparently associated with very small amount ofMn4+ ions. The covalent component of the chemical bond and e.g.-orbitals disordering/mixing are assumed to be responsible for ferromagnetism in the compounds under study.
BibTeX: @article{Troyanchuk2018, author = {Troyanchuk, I.O. and Bushinsky, M.V. and Tereshko, N.V. and Sirenko, V.A. and Sikolenko, V. and Schorr, S. and Ritter, C. and Franz, A.}, title = {Ferromagnetic ordering, magnetic and magnetotransport properties of R1-xSrx(Mn1-x/2Sbx/2)O3 (R = La, Pr, Nd, Sm, Eu) manganites}, journal = {Materials Research Express}, publisher = {Institute of Physics Publishing}, year = {2018}, volume = {5}, number = {6}, pages = {066101}, doi = {http://dx.doi.org/10.1088/2053-1591/aac7b8} }
Panfilov A., Grechnev G., Zhuravleva I., Lyogenkaya A., Pashchenko V., Savenko B., Novoselov D., Prabhakaran D., Troyanchuk I.	Pressure effect on magnetic susceptibility of LaCoO3 [Abstract] [BibTeX]	2018	Low Temperature Physics Vol. 44(4), pp. 328-333	DOI
Abstract: The effect of pressure on magnetic properties of LaCoO3 is studied experimentally and theoretically. The pressure dependence of magnetic susceptibility χ of LaCoO3 is obtained by precise measurements of χ as a function of the hydrostatic pressure P up to 2 kbar in the temperature range from 78 K to 300 K. A pronounced magnitude of the pressure effect is found to be negative in sign and strongly temperature dependent. The obtained experimental data are analysed by using a two-level model and DFT+U calculations of the electronic structure of LaCoO3. In particular, the fixed spin moment method was employed to obtain a volume dependence of the total energy difference Δ between the low spin and the intermediate spin states of LaCoO3. Analysis of the obtained experimental χ(P) dependence within the two-level model, as well as our DFT+U calculations, have revealed the anomalous large decrease in the energy difference Δ with increasing of the unit cell volume. This effect, taking into account a thermal expansion, can be responsible for the temperatures dependence of Δ, predicting its vanishing near room temperature.
BibTeX: @article{Panfilov2018328, author = {Panfilov, A.S. and Grechnev, G.E. and Zhuravleva, I.P. and Lyogenkaya, A.A. and Pashchenko, V.A. and Savenko, B.N. and Novoselov, D. and Prabhakaran, D. and Troyanchuk, I.O.}, title = {Pressure effect on magnetic susceptibility of LaCoO3}, journal = {Low Temperature Physics}, year = {2018}, volume = {44}, number = {4}, pages = {328-333}, doi = {http://dx.doi.org/10.1063/1.5030456} }
Budnyk M., Minov Y., Lyakhno V., Desnenko V., Linnik A., Shopen O.	Development of improved superconductive axial gradiometers for biomagnetic SQUID applications [Abstract] [BibTeX]	2018	Low Temperature Physics Vol. 44(3), pp. 233-237	DOI
Abstract: SQUID magnetometers for biomagnetic measurements are equipped with superconductive gradiometers which are required to provide a high signal-to-noise ratio at low frequencies, sufficient mechanical strength and sustained performance under repeated thermal cycles, as well as a low level of intrinsic magnetic noise. This paper describes the design of a gradiometer made with a carbon-fiber reinforced composite material for magnetic cardiography measurements. The thermal coefficient of linear expansion (TCLE) of the carbon fiber composite can be precisely adjusted to match that of the superconducting detector coil wire. This is achieved thanks to the difference in the TCLE of carbon fibers in the longitudinal and transverse directions and is realized by varying the laying directions of the fiber in the composite. The data of magnetic susceptibility measurements on carbon fiber composite are reported, showing the magnetic susceptibility about six times smaller than that of graphite. The presented gradiometer design provides a high degree of balancing and is patented along side other specific techniques.
BibTeX: @article{Budnyk2018233, author = {Budnyk, M.M. and Minov, Y.D. and Lyakhno, V.Y. and Desnenko, V.A. and Linnik, A.S. and Shopen, O.B.}, title = {Development of improved superconductive axial gradiometers for biomagnetic SQUID applications}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2018}, volume = {44}, number = {3}, pages = {233-237}, doi = {http://dx.doi.org/10.1063/1.5024543} }
Eremenko V., Sirenko V., Baran A., Čižmár E., Feher A.	Spin-glass polyamorphism induced by a magnetic field in LaMnO3 single crystal [Abstract] [BibTeX]	2018	Journal of Physics Condensed Matter Vol. 30(20), pp. 205801	DOI
Abstract: We present experimental evidence of field-driven transition in spin-glass state, similar to pressure-induced transition between amorphous phases in structural and metallic glasses, attributed to the polyamorphism phenomena. Cusp in temperature dependences of ac magnetic susceptibility of weakly disordered LaMnO3 single crystal is registered below the temperature of magnetic ordering. Frequency dependence of the cusp temperature proves its spin-glass origin. The transition induced by a magnetic field in spin-glass state, is manifested by peculiarity in dependence of cusp temperature on applied magnetic field. Field dependent maximum of heat capacity is observed in the same magnetic field and temperature range.
BibTeX: @article{Eremenko2018, author = {Eremenko, V.V. and Sirenko, V.A. and Baran, A. and Čižmár, E. and Feher, A.}, title = {Spin-glass polyamorphism induced by a magnetic field in LaMnO3 single crystal}, journal = {Journal of Physics Condensed Matter}, publisher = {Institute of Physics Publishing}, year = {2018}, volume = {30}, number = {20}, pages = {205801}, doi = {http://dx.doi.org/10.1088/1361-648X/aabc9d} }
Eremenko V., Sirenko V., Gospodarev I., Syrkin E., Feodosyev S., Bondar I., Minakova K., Feher A.	Electron spectra of graphene with local and extended defects [Abstract] [BibTeX]	2018	Journal of Physics: Conference Series Vol. 969(1), pp. 012021	DOI
Abstract: We show theoretically a possibility to increase the superconducting transition temperature Tc of graphene by introducing defects. Eventually, the peak of local electron densities shifts to the Fermi level with Tc above ambient temperature in line with recent observations.
BibTeX: @conference{Eremenko2018c, author = {Eremenko, V.V. and Sirenko, V.A. and Gospodarev, I.A. and Syrkin, E.S. and Feodosyev, S.B. and Bondar, I.S. and Minakova, K.A. and Feher, A.}, title = {Electron spectra of graphene with local and extended defects}, journal = {Journal of Physics: Conference Series}, publisher = {Institute of Physics Publishing}, year = {2018}, volume = {969}, number = {1}, pages = {012021}, doi = {http://dx.doi.org/10.1088/1742-6596/969/1/012021} }
Šoltésová D., Vasylets G., Čižmár E., Fedorchenko A., Starodub V., Medviediev V., Shishkin O., Bukrynov O., Feher A.	Magnetic properties of the anion-radical salts [M(bipy)3](TCNQ)4·X, where M = Co, Ni, Zn and X = H2O or (CH3)2CO [Abstract] [BibTeX]	2018	Inorganica Chimica Acta Vol. 471, pp. 272-279	DOI
Abstract: An anion-radical salt (ARS) [Co(bipy)3](TCNQ)4·H2O was synthesized and its crystal structure was resolved. The experimental investigation of [Co(bipy)3](TCNQ)4·H2O and two ARS with similar crystal structure [Zn(bipy)3](TCNQ)4·H2O and [Ni(bipy)3](TCNQ)4·(CH3)2CO by the measurement of the temperature dependence of magnetic susceptibility at temperature from 1.8 K to 300 K, the field dependence of magnetization up to 7 T at different temperatures and EPR spectra in temperature range from 2 K to 300 K was performed. [Zn(bipy)3](TCNQ)4·H2O was used to estimate the contribution of the TCNQ radicals to the magnetic moment. In result, the compound [Co(bipy)3](TCNQ)4·H2O was characterized by the presence of Co2+ ions in spin-admixed state and low-temperature susceptibility, magnetization and specific heat of [Ni(bipy)3](TCNQ)4·(CH3)2CO was shown to be dominated by the contribution of single-ion anisotropy of Ni2+ ions.
BibTeX: @article{Soltesova2018272, author = {Šoltésová, D. and Vasylets, G. and Čižmár, E. and Fedorchenko, A.V. and Starodub, V. and Medviediev, V. and Shishkin, O. and Bukrynov, O. and Feher, A.}, title = {Magnetic properties of the anion-radical salts [M(bipy)3](TCNQ)4·X, where M = Co, Ni, Zn and X = H2O or (CH3)2CO}, journal = {Inorganica Chimica Acta}, publisher = {Elsevier S.A.}, year = {2018}, volume = {471}, pages = {272-279}, doi = {http://dx.doi.org/10.1016/j.ica.2017.11.001} }
Eremenko V., Sirenko V., Dolbin A., Feodosyev S., Gospodarev I., Syrkin E., Bondar I., Minakova K.	The phonon mediated anomalies of thermal expansion in transition-metal componds and emergent nanostructures [Abstract] [BibTeX]	2017	Solid State Phenomena Vol. 257, pp. 81-85	DOI
Abstract: The negative expansion observed at low temperatures in specific crystallographic directions of complex structures with anisotropic interactions is explained by microscopic analysis within the tight-binding, quasi-harmonic approximation of lattice dynamics [1]. The results agree with measurements on multilayer sandwiches of transition-metal dichalcogenides, high-temperature superconductors and relevant nanostructures including the carbon-based nanotubes.
BibTeX: @article{Eremenko201781, author = {Eremenko, V. and Sirenko, V. and Dolbin, A. and Feodosyev, S. and Gospodarev, I. and Syrkin, E. and Bondar, I. and Minakova, K.}, title = {The phonon mediated anomalies of thermal expansion in transition-metal componds and emergent nanostructures}, journal = {Solid State Phenomena}, publisher = {Trans Tech Publications Ltd}, year = {2017}, volume = {257}, pages = {81-85}, doi = {http://dx.doi.org/10.4028/www.scientific.net/SSP.257.81} }
Fedorchenko A., Fertman E., Desnenko V., Kotlyar O., Čižmár E., Shvartsman V., Lupascu D., Salamon S., Wende H., Salak A., Khalyavin D., Olekhnovich N., Pushkarev A., Radyush Y., Feher A.	Magnetic properties of the Bi0.65La0.35Fe0.5Sc0.5O3 perovskite [Abstract] [BibTeX]	2017	Acta Physica Polonica A Vol. 131(4), pp. 1069-1071	DOI
Abstract: Magnetic properties of polycrystalline multiferroic Bi0.65La0.35Fe0.5Sc0.5O3 synthesized under high-pressure (6 GPa) and high-temperature (1500 K) conditions were studied using a SQUID magnetometer technique. The temperature dependent static magnetic moment M was measured in both zero-field-cooled and field-cooled modes over the temperature range of 5-300 K in low magnetic field H = 0.02 kOe. The field dependent magnetization M(H) was measured in magnetic fields up to 50 kOe at different temperatures up to 230 K after zero-field cooling procedure. A long-range magnetic ordering of the antiferromagnetic type with a weak ferromagnetic contribution takes place below TN ≈ 220 K. Magnetic hysteresis loops taken below TN show a huge coercive field up to Hc ≈ 10 kOe, while the magnetic moment does not saturate up to 50 kOe. A strong effect of magnetic field on the magnetic properties of the compound has been found. Below TN ≈ 220 K the derivatives of the initial magnetization curves demonstrate the existence of a temperature-dependent anomaly in fields of H = 15÷25 kOe. The nature of the anomaly is unknown and requires additional study.
BibTeX: @article{Fedorchenko20171069, author = {Fedorchenko, A.V. and Fertman, E.L. and Desnenko, V.A. and Kotlyar, O.V. and Čižmár, E. and Shvartsman, V.V. and Lupascu, D.C. and Salamon, S. and Wende, H. and Salak, A.N. and Khalyavin, D.D. and Olekhnovich, N.M. and Pushkarev, A.V. and Radyush, Yu.V. and Feher, A.}, title = {Magnetic properties of the Bi0.65La0.35Fe0.5Sc0.5O3 perovskite}, journal = {Acta Physica Polonica A}, publisher = {Polish Academy of Sciences}, year = {2017}, volume = {131}, number = {4}, pages = {1069-1071}, doi = {http://dx.doi.org/10.12693/APhysPolA.131.1069} }
Fertman E.L., Fedorchenko A.V., Khalyavin D.D., Salak A.N., Baran A., Desnenko V.A., Kotlyar O.V., Čižmár E., Feher A., Syrkin E.S., Vaisburd A.I., Olekhnovich N.M., Pushkarev A.V., Radyush Y.V., Stanulis A., Kareiva A.	Multiferroic Bi0.65La0.35Fe0.5Sc0.5O3 perovskite: Magnetic and thermodynamic properties [Abstract] [BibTeX]	2017	Journal of Magnetism and Magnetic Materials Vol. 429, pp. 177-181	DOI
Abstract: Magnetic and thermodynamic properties of polycrystalline multiferroic Bi0.65La0.35Fe0.5Sc0.5O3 synthesized under high-pressure and high-temperature conditions are reported. Magnetic properties were studied using a SQUID magnetometer technique over the temperature range of 5−300 K in magnetic fields up to H=10 kOe. The field dependent magnetization M(H) was measured in magnetic fields up to 50 kOe at different temperatures up to 230 K after zero-field cooling procedure. A long-range magnetic ordering of the AFM type with a weak FM contribution occurs below the Néel temperature TN ~237 K. Magnetic hysteresis loops taken below TN show a huge coercive field up to Hc ~10 kOe. A strong effect of magnetic field on the magnetic properties of the compound has been found. Derivative of the initial magnetization curves demonstrates a temperature-dependent anomaly in fields of H=15−25 kOe. Besides, an anomaly of the temperature dependent zero-field cooled magnetization measured in magnetic fields of 6−7 kOe has been found. Origin of both anomalies is associated with inhomogeneous magnetic state of the compound. The heat capacity has been measured from 2 K up to room temperature and a significant contribution from the magnon excitations at low temperatures has been detected. From the low-temperature heat capacity, an anisotropy gap of the magnon modes of the order 3.7 meV and Debye temperature TD=189 K have been determined.
BibTeX: @article{Fertman2017177, author = {Fertman, E. L. and Fedorchenko, A. V. and Khalyavin, D. D. and Salak, A. N. and Baran, A. and Desnenko, V. A. and Kotlyar, O. V. and Čižmár, E. and Feher, A. and Syrkin, E. S. and Vaisburd, A. I. and Olekhnovich, N. M. and Pushkarev, A. V. and Radyush, Yu. V. and Stanulis, A. and Kareiva, A.}, title = {Multiferroic Bi0.65La0.35Fe0.5Sc0.5O3 perovskite: Magnetic and thermodynamic properties}, journal = {Journal of Magnetism and Magnetic Materials}, publisher = {Elsevier B.V.}, year = {2017}, volume = {429}, pages = {177-181}, doi = {http://dx.doi.org/10.1016/j.jmmm.2017.01.037} }
Fil V., Kolodyazhnaya M., Zvyagina G., Bilych I., Zhekov K.	Piezomagnetoelectric effect in LiCoPO4 [Abstract] [BibTeX]	2017	Physical Review B Vol. 96(18), pp. 180407(R)	DOI
Abstract: The piezomagnetoelectric effect is considered to be the appearance of a piezoelectric response caused by a magnetic field in magnetically ordered media. The possibility of its existence in antiferromagnets was predicted in the 1960's; however, attempts at its experimental detection were unsuccessful. In this Rapid Communication, our experiments confirm the appearance of the piezomagnetoelectric effect in a LiCoPO4 single crystal.
BibTeX: @article{Fil2017, author = {Fil, V.D. and Kolodyazhnaya, M.P. and Zvyagina, G.A. and Bilych, I.V. and Zhekov, K.R.}, title = {Piezomagnetoelectric effect in LiCoPO4}, journal = {Physical Review B}, publisher = {American Physical Society}, year = {2017}, volume = {96}, number = {18}, pages = {180407(R)}, doi = {http://dx.doi.org/10.1103/PhysRevB.96.180407} }
Kolodyazhnaya M., Zvyagina G., Bilych I., Zhekov K., Kharchenko N., Fil V.	Is LiCoPO4 a pyroelectric? [Abstract] [BibTeX]	2017	Low Temperature Physics Vol. 43(10), pp. 1240-1242	DOI
Abstract: The acoustoelectric transformation in single-crystal LiCoPO4 is studied. At temperatures corresponding to the paramagnetic phase, a piezoresponse to longitudinal elastic deformation parallel to the crystallographic a axis is observed. Arguments are introduced in support of identifying this compound as pyroelectric, as opposed to the generally accepted viewpoint which assigns it to the class of centrally symmetric crystals.
BibTeX: @article{Kolodyazhnaya20171240, author = {Kolodyazhnaya, M.P. and Zvyagina, G.A. and Bilych, I.V. and Zhekov, K.R. and Kharchenko, N.F. and Fil, V.D.}, title = {Is LiCoPO4 a pyroelectric?}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2017}, volume = {43}, number = {10}, pages = {1240-1242}, doi = {http://dx.doi.org/10.1063/1.5008421} }
Kolodyazhnaya M., Zvyagina G., Gudim I., Bilych I., Burma N., Zhekov K., Fil V.	Piezoelectric response in SmFe3(BO3)4, a non-piezoactive configuration. The surface piezoelectric effect [Abstract] [BibTeX]	2017	Low Temperature Physics Vol. 43(8), pp. 924-929	DOI
Abstract: An investigation of the mechanisms responsible for the manifestation of the piezoelectric effect in configurations that should not allow for piezoelectric response in the paramagnetic state due to their symmetry. In spite of these symmetry constraints the existence of such a piezoelectric response is detected in this study. It is assumed that these results are associated with the surface on which symmetry constraints are absent. In the magnetically ordered state an indirect piezoelectric effect is both symmetrically permissible and actually observable in these configurations, and it consists of the combined effects of magnetoelectric and magnetoelastic mechanisms.
BibTeX: @article{Kolodyazhnaya2017924, author = {Kolodyazhnaya, M.P. and Zvyagina, G.A. and Gudim, I.A. and Bilych, I.V. and Burma, N.G. and Zhekov, K.R. and Fil, V.D.}, title = {Piezoelectric response in SmFe3(BO3)4, a non-piezoactive configuration. The surface piezoelectric effect}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2017}, volume = {43}, number = {8}, pages = {924-929}, doi = {http://dx.doi.org/10.1063/1.5001291} }
Panfilov A., Grechnev G., Chareev D., Polkovnikov A., Andreev O.	Pressure effect on magnetic susceptibility of SmS in the “black” phase [Abstract] [BibTeX]	2017	Journal of Alloys and Compounds Vol. 695, pp. 1647-1652	DOI
Abstract: New experimental results on the pressure dependence of magnetic susceptibility χ of SmS in semiconducting phase are obtained with precise measurements of χ as a function of the hydrostatic pressure P up to 2 kbar at liquid nitrogen and room temperatures. A pronounced magnitude of the pressure effect is found to be positive in sign and strongly temperature dependent: the pressure derivatives of χ, d lnχ/dP, are 6.3 ± 0.5 and 14.2 ± 1 Mbar−1 at 300 and 78 K, respectively. The experimental results are supplemented by theoretical calculations of the volume dependent electronic structure of SmS and orbital magnetism of the band electronic states χVV(band). It was found that χVV(band) value appeared to be strongly dependent on pressure, determining the main mechanism of the observed puzzling pressure effects in semiconducting SmS compound.
BibTeX: @article{Panfilov20171647, author = {Panfilov, A.S. and Grechnev, G.E. and Chareev, D.A. and Polkovnikov, A.A. and Andreev, O.V.}, title = {Pressure effect on magnetic susceptibility of SmS in the “black” phase}, journal = {Journal of Alloys and Compounds}, publisher = {Elsevier Ltd}, year = {2017}, volume = {695}, pages = {1647-1652}, doi = {http://dx.doi.org/10.1016/j.jallcom.2016.10.311} }
Prikhna T., Romaka V., Shapovalov A., Eisterer M., Sokolovsky V., Weber H., Grechnev G., Boutko V., Gusev A., Kozyrev A., Goldacker W., Moshchil V., Sverdun V., Habisreuther T., Schmidt C., Kovylaev V., Shaternik V., Karpets M., Shaternik A.	Structure and Properties of MgB2 Bulks, Thin Films, and Wires [Abstract] [BibTeX]	2017	IEEE Transactions on Applied Superconductivity Vol. 27(4), pp. 6200705	DOI
Abstract: This paper describes the established correlations between the characteristics of MgB2-based superconducting materials and their structural features, in particular the oxygen distribution and content. As indicated by SEM and Auger analysis, a sizeable amount of oxygen is usually present in superconducting MgB2 -based materials (bulks, thin films, and wires). The matrix phase of bulk MgB2 contains rather small amounts of oxygen, but contains a high amount of dispersed inclusions or areas with compositions close to MgBO. X-ray phase analysis with Rietveld refinement (using the FullProf Suite program package) of several highly dense MgB2 -based bulk samples (with high critical current densities) showed that the superconducting phase had a composition within the range MgB1.68O0.26 and MgB1.74O0.32 instead of pure MgB2. Besides, a small amount of a phase with MgO structure was observed in the materials by X-rays as well. The calculation of the enthalpy of formation confirms the possibility of oxygen solubility in MgB2 and shows that the formation of MgB1.75B0.25 is most favorable. The results of ab initio calculations of the electronic structure and stability of the MgB2 compounds with partial oxygen substitution for boron show that it is energetically preferable for oxygen atoms to replace boron pairwise.
BibTeX: @article{Prikhna2017, author = {Prikhna, T.A. and Romaka, V.V. and Shapovalov, A.P. and Eisterer, M. and Sokolovsky, V. and Weber, H.W. and Grechnev, G.E. and Boutko, V.G. and Gusev, A.A. and Kozyrev, A.V. and Goldacker, W. and Moshchil, V.E. and Sverdun, V.B. and Habisreuther, T. and Schmidt, C. and Kovylaev, V.V. and Shaternik, V.E. and Karpets, M.V. and Shaternik, A.V.}, title = {Structure and Properties of MgB2 Bulks, Thin Films, and Wires}, journal = {IEEE Transactions on Applied Superconductivity}, publisher = {Institute of Electrical and Electronics Engineers Inc.}, year = {2017}, volume = {27}, number = {4}, pages = {6200705}, doi = {http://dx.doi.org/10.1109/TASC.2016.2638201} }
Prikhna T., Shapovalov A., Eisterer M., Shaternik V., Goldacker W., Weber H., Moshchil V., Kozyrev A., Sverdun V., Boutko V., Grechnev G., Gusev A., Kovylaev V., Shaternik A.	Pinning in high performance MgB2 thin films and bulks: Role of Mg-B-O nano-scale inhomogeneities [Abstract] [BibTeX]	2017	Physica C: Superconductivity and its Applications Vol. 533, pp. 36-39	DOI
Abstract: The comparison of nano-crystalline MgB2 oxygen-containing thin film (140 nm) and highly dense bulk materials showed that the critical current density, Jc, depends on the distribution of Mg-B-O nano-scale inhomogeneities. It has been shown that MgB2 bulks with high Jc in low (∼106 A/cm2 in 0-1 T at 10 K) and medium magnetic fields contain MgB0.6-0.8O0.8-0.9 nano-inclusions, where δTc or a combined δTc (dominant) / δl pinning mechanism prevails, while in bulk MgB2 with high Jc in high magnetic fields (Birr(18.5 K) = 15 T, Bc2(0 K) = 42.1 T) MgB1.2-2.7O1.8-2.5 nano-layers are present and δl pinning prevails. The structure of oxygen-containing films with high Jc in low and high magnetic fields (Jc (0 Т) = 1.8 × 107 А/сm2 and Jc (5 Т) = 2 × 106 А/сm2 at 10 К) contains very fine oxygen-enriched Mg-B-O inhomogeneities and δl pinning is realized. The results of DOS calculations in MgB2-xOx cells for x = 0, 0.125, 0.25, 0.5, 1 demonstrate that all compounds are conductors with metal-like behaviour. In the case of ordered oxygen substitution for boron the binding energy, Eb, does not increase sufficiently as compared with that for MgB2, while when oxygen atoms form zigzag chains the calculated Eb is even lower (Eb = −1.15712 Ry).
BibTeX: @article{Prikhna201736, author = {Prikhna, T. and Shapovalov, A. and Eisterer, M. and Shaternik, V. and Goldacker, W. and Weber, H.W. and Moshchil, V. and Kozyrev, A. and Sverdun, V. and Boutko, V. and Grechnev, G. and Gusev, A. and Kovylaev, V. and Shaternik, A.}, title = {Pinning in high performance MgB2 thin films and bulks: Role of Mg-B-O nano-scale inhomogeneities}, journal = {Physica C: Superconductivity and its Applications}, publisher = {Elsevier B.V.}, year = {2017}, volume = {533}, pages = {36-39}, doi = {http://dx.doi.org/10.1016/j.physc.2016.08.002} }
Prikhna T., Romaka V., Eisterer M., Shapovalov A., Kozyrev A., Grechnev G., Boutko V., Goldacker W., Habisreuther T., Vakaliuk O., Halbedel B.	Structure and superconducting characteristics of magnesium diboride, substitution of boron atoms by oxygen and carbon [Abstract] [BibTeX]	2017	IOP Conference Series: Materials Science and Engineering Vol. 279(1), pp. 012023	DOI
Abstract: An x-ray analysis of MgB2-based materials shows that they contain MgB2 and MgO phases. According to a quantitative Auger analysis (taken after removing the oxidized surface layer by Ar ion etching in the microscope chamber) the MgB2 phase contains some amount of oxygen that approximately corresponds to the composition MgB2.2-1.7O0.4-0.6. Rietveld refinement of the MgB2 phase, based on EDX data with varying B/O content, leads to the composition MgB1.68-1.8O0.2-0.32. Ab-initio modelling of boron substitution by oxygen in MgB2 (ΔH f = -150.6 meV/atom) shows that this is energetically favourable up to the composition MgB1.75O0.25 (ΔH f = -191.4 meV/atom). In contrast to carbon substitution, where very small levels of doping can dramatically affect the superconducting characteristics of the material with concomitant changes in the electron density, oxygen substitution results in very little change in the superconducting properties of MgB2. The formation of vacancies at the Mg site of both MgB2 and substituted MgB1.75O0.25 was modelled as well, but has shown that such processes are energetically disadvantageous (ΔHf of Mg0.875B2 and Mg0.75B1.75O0.25 are equal to -45.5 and -93.5 meV/atom, respectively).
BibTeX: @conference{Prikhna2017a, author = {Prikhna, T. and Romaka, V. and Eisterer, M. and Shapovalov, A. and Kozyrev, A. and Grechnev, G. and Boutko, V. and Goldacker, W. and Habisreuther, T. and Vakaliuk, O. and Halbedel, B.}, title = {Structure and superconducting characteristics of magnesium diboride, substitution of boron atoms by oxygen and carbon}, journal = {IOP Conference Series: Materials Science and Engineering}, publisher = {Institute of Physics Publishing}, year = {2017}, volume = {279}, number = {1}, pages = {012023}, doi = {http://dx.doi.org/10.1088/1757-899X/279/1/012023} }
Troyanchuk I., Karpinsky D., Bushinsky M., Sirenko V., Sikolenko V., Franz A.	Antiferromagnet-ferromagnet transition in La_1-xSr_xMn_0.5Ni_0.5O₃ (0≤x≤0.2) ceramics [Abstract] [BibTeX]	2017	Low Temperature Physics Vol. 43(8), pp. 982-985	DOI
Abstract: Ceramics samples of La1-xSrxMn0.5Ni0.5O3 (0≤x≤0.2) with perovskite structure have been studied by neutron diffraction method, magnetometry and magnetoresistance measurements. Structural data testify a partial order of the Ni and Mn ions in all the compounds in spite of chemical substitution of the La3+ ions by Sr2+ ones and an increase of the oxidation state of the Ni ions from 2+ towards to 3+ one. Magnetic structure of the compounds changes from ferromagnetic one (specific for the compound with x=0) to antiferromagnetic (compounds with x ≥ 0.1) while the temperature of a transition into paramagnetic state remains about 270K for all the samples. Magnetoresistance gradually decreases with temperature increase and strontium content. The results are discussed assuming nearly equal ferromagnetic and antiferromagnetic components of the superexchange interaction Ni2+-O-Mn4+ while the interaction between Ni3+ and Mn4 ions is considered to be strongly antiferromagnetic.
BibTeX: @article{Troyanchuk2017982, author = {Troyanchuk, I.O. and Karpinsky, D.V. and Bushinsky, M.V. and Sirenko, V.A. and Sikolenko, V.V. and Franz, A.}, title = {Antiferromagnet-ferromagnet transition in La_1-xSr_xMn_0.5Ni_0.5O₃ (0≤x≤0.2) ceramics}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2017}, volume = {43}, number = {8}, pages = {982-985}, doi = {http://dx.doi.org/10.1063/1.5001300} }
Vieira D., Salak A., Fedorchenko A., Pashkevich Y., Fertman E., Desnenko V., Babkin R., Čižmár E., Feher A., Lopes A., Ferreira M.	Magnetic phenomena in Co-containing layered double hydroxides [Abstract] [BibTeX]	2017	Low Temperature Physics Vol. 43(8), pp. 1214-1218	DOI
Abstract: Magnetic behavior of CoII(n)AlIII layered double hydroxides (LDHs) (n=Co/Al=2 and 3) intercalated with nitrate was studied as a function of temperature. Both LDH compounds are paramagnetic above about 8K. A rapid increase of their magnetic moments occurs below this temperature until the moments reach the maximum values at Tmax of 4.0K and 3.2K for Co(2)Al-NO3 and Co(3)Al-NO3, respectively. Below Tmax, the zero-field-cooled and the field-cooled static magnetization curves are strongly different. Along with this low-temperature phenomena, Co(2)Al-NO3 and Co(3)Al-NO3 demonstrate anomalous behavior of their temperature dependence magnetic susceptibility in a highertemperature range: between 75 and 175K, both the paramagnetic Curie temperature and the effective magnetic moment change in a non-monotonous way. Possible structural reasons of the observed magnetic behavior of the CoII(n)AlIII LDHs are discussed.
BibTeX: @article{Vieira20171214, author = {Vieira, D.E.L. and Salak, A.N. and Fedorchenko, A.V. and Pashkevich, Y.G. and Fertman, E.L. and Desnenko, V.A. and Babkin, R.Y. and Čižmár, E. and Feher, A. and Lopes, A.B. and Ferreira, M.G.S.}, title = {Magnetic phenomena in Co-containing layered double hydroxides}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2017}, volume = {43}, number = {8}, pages = {1214-1218}, doi = {http://dx.doi.org/10.1063/1.5001299} }
Zhuravleva I., Grechnev G., Panfilov A., Lyogenkaya A.	Magnetovolume effect in the exchange-enhanced itinerant paramagnet YCo2: Theory and experiment [Abstract] [BibTeX]	2017	Low Temperature Physics Vol. 43(5), pp. 597-601	DOI
Abstract: A detailed theoretical study of the anomalous magnetovolume effect in the exchange-enhanced itinerant paramagnet YCo2 was carried out based on DFT calculations of the electronic structure in an external magnetic field and further complemented with the experimental data on the behavior of the magnetic susceptibility χ under high hydrostatic pressure. The calculations of the magnetic susceptibility and magnetovolume effect dlnχ/dlnV are in reasonable agreement with the experimental data, indicating the proximity of YCo2 to the ferromagnetic instability.
BibTeX: @article{Zhuravleva2017597, author = {Zhuravleva, I.P. and Grechnev, G.E. and Panfilov, A.S. and Lyogenkaya, A.A.}, title = {Magnetovolume effect in the exchange-enhanced itinerant paramagnet YCo2: Theory and experiment}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2017}, volume = {43}, number = {5}, pages = {597-601}, doi = {http://dx.doi.org/10.1063/1.4985217} }
Бурма М.Г., Поліщук В.М., Рой В.Ф.	Регулювання режимами роботи електричних кіл освітлювальних установок [BibTeX]	2017	Вісник Національного технічного університету "ХПІ". Серія : Проблеми удосконалення електричних машин і апаратів. Теорія і практика Vol. 34, pp. 51-55	URL
BibTeX: @article{burma2017, author = {Бурма, М. Г. and Поліщук, В. М. and Рой, В. Ф.}, title = {Регулювання режимами роботи електричних кіл освітлювальних установок}, journal = {Вісник Національного технічного університету "ХПІ". Серія : Проблеми удосконалення електричних машин і апаратів. Теорія і практика}, year = {2017}, volume = {34}, pages = {51-55}, url = {http://www.irbis-nbuv.gov.ua/cgi-bin/irbis_nbuv/cgiirbis_64.exe?I21DBN=LINK&P21DBN=UJRN&Z21ID=&S21REF=10&S21CNR=20&S21STN=1&S21FMT=ASP_meta&C21COM=S&2_S21P03=FILA=&2_S21STR=vsrudmash_2017_34_11} }
Bondar I., Pinegin V., Ryabovol V., Sirenko V., Eremenko V.	Combi-cryostat for a X-ray diffractometer [Abstract] [BibTeX]	2017	Low Temperature Physics Vol. 43(12), pp. 1432	DOI
Abstract: A compact helium combi-cryostat (bath+ continuous flow) was designed and manufactured for the purposes of studying samples using x-ray diffraction.
BibTeX: @article{Bondar20171432, author = {Bondar, I.S. and Pinegin, V.I. and Ryabovol, V.V. and Sirenko, V.A. and Eremenko, V.V.}, title = {Combi-cryostat for a X-ray diffractometer}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2017}, volume = {43}, number = {12}, pages = {1432}, doi = {http://dx.doi.org/10.1063/1.5012797} }
Eremenko V., Sirenko V., Gospodarev I., Syrkin E., Feodosyev S., Bondar I., Feher A., Minakova K.	Electron and phonon states localized near the graphene boundary [Abstract] [BibTeX]	2017	Low Temperature Physics Vol. 43(11), pp. 1323-1331	DOI
Abstract: We perform analytical and numerical analysis of the electronic and phonon spectrum evolution of graphene during formation of a boundary with a "zigzag" chirality. It is determined, that the excited gap wave has a relativistic dispersion near the Fermi level that propagates along the boundary and decays with distance from it. Both properties and formation of the wave is considered. It is shown that the wave propagation occurs only along the atoms of the sub-lattice, which contains atoms with bonds broken during the boundary formation. The gap wave forms narrow resonance peaks in the local density of states of the sublattice atoms. It is shown, that the boundary formation on a graphene layer with this chirality similarly affects the phonon modes polarized normal to the layer, forming narrow maxima with frequencies nearing that of the quasiflexural phonons with the quasiwave vector at the K-point of the first Brillouin zone. This way, the formation of the "zigzag"-boundary increases both the number of charge carriers as well as the number of phonons with a large group velocity that can cause a large contribution to the electron-phonon interactions.
BibTeX: @article{Eremenko20171323, author = {Eremenko, V.V. and Sirenko, V.A. and Gospodarev, I.A. and Syrkin, E.S. and Feodosyev, S.B. and Bondar, I.S. and Feher, A. and Minakova, K.A.}, title = {Electron and phonon states localized near the graphene boundary}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2017}, volume = {43}, number = {11}, pages = {1323-1331}, doi = {http://dx.doi.org/10.1063/1.5010320} }
Kolodyazhnaya M., Zhekov K., Bilych I., Zvyagina G., Zvyagin A.	Reentrant low-temperature phase transition in an "orbital nematic" [Abstract] [BibTeX]	2017	Low Temperature Physics Vol. 43(11), pp. 1276-1282	DOI
Abstract: The influence of an external magnetic field on the Jahn-Teller phase transition at Tc ≈ 14 K was studied in a KDy(MoO4)2 single crystal. At temperatures below Tc a significant change in the velocity and attenuation of the acoustic modes of the crystal was observed for the magnetic field oriented along the [110] direction. This behavior of the elastic characteristics occurs due to the destruction of the antiferrodistortive ordering, which is, in turn, coupled with the ordering of the quadrupole orbital moments, characteristic for an "orbital nematic." The low-temperature region of the H-T phase diagram for this direction of the field was reconstructed. It was found that the magnetic field dependence of the critical temperature is nonmonotonic, i.e., the phase transition has the reentrant character. Theoretical description of the observed anomalies of the temperature and magnetic field behavior of the acoustic characteristics was given.
BibTeX: @article{Kolodyazhnaya20171276, author = {Kolodyazhnaya, M.P. and Zhekov, K.R. and Bilych, I.V. and Zvyagina, G.A. and Zvyagin, A.A.}, title = {Reentrant low-temperature phase transition in an "orbital nematic"}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2017}, volume = {43}, number = {11}, pages = {1276-1282}, doi = {http://dx.doi.org/10.1063/1.5010312} }
Pashchenko V., Galetich I., Sirenko V., Eremenko V., Eremenko A., Brook V.	The magnetic state of the weakly anion-excess manganite LaMnO3+δ [Abstract] [BibTeX]	2017	Low Temperature Physics Vol. 43(11), pp. 1305-1310	DOI
Abstract: This paper deals with the magnetic state of the weakly anion-excess lanthanum manganite LaMnO3+δ (δ ≈ 0.0375). The temperature and field dependences of the magnetic moment of single crystal samples are studied in detail for temperatures of 2-350 K in different fields up to 5 T along the c-axis. The field dependence of the observed singular temperature points, such as those for magnetic ordering, magnetic vitrification, and magnetic phase separation, is recovered. The magnetic field behavior of several of the singular points is found to be interrelated. These results are fully consistent with models of magnetic phase separation that predict the formation of self-localized states such as nanoscale ferromagnetic droplets in a bulk antiferromagnetic matrix.
BibTeX: @article{Pashchenko20171305, author = {Pashchenko, V.A. and Galetich, I.K. and Sirenko, V.A. and Eremenko, V.V. and Eremenko, A.V. and Brook, V.V.}, title = {The magnetic state of the weakly anion-excess manganite LaMnO3+δ}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2017}, volume = {43}, number = {11}, pages = {1305-1310}, doi = {http://dx.doi.org/10.1063/1.5010317} }
Bilych I., Zhekov K., Gaydamak T., Gudim I., Zvyagina G., Fil V.	Magnetodielectrical and magnetopiezoelectrical effects in NdFe3(BO3)4 [Abstract] [BibTeX]	2016	Low Temperature Physics Vol. 42(12), pp. 1112-1119	DOI
Abstract: Magnetodielectric (magnetocapacitance) and magnetopiezoelectric effects in neodymium ferroborate are systematically investigated. The existence of a previously observed magnetopiezoelectric effect in samarium ferroborate is confirmed. This effect consists in indirect renormalization of the piezoelectric modulus as a result of the combined action of the magnetoelectric and magnetoelastic mechanisms. The manifestation of a new type of phenomena-direct renormalization of the piezoelectric interaction in a magnetically ordered phase-is observed. The ratio of the contributions of the rare-earth and iron systems to the magnetoelectric interaction is estimated. It is shown that the latter plays a ballast role, impeding orientation fluctuations of the magnetic structure as a whole. The boundaries of existence of the helicoidal phase on the H-T plane are determined. The phenomenological interpretation of the studied effects is given.
BibTeX: @article{Bilych20161112, author = {Bilych, I.V. and Zhekov, K.R. and Gaydamak, T.N. and Gudim, I.A. and Zvyagina, G.A. and Fil, V.D.}, title = {Magnetodielectrical and magnetopiezoelectrical effects in NdFe3(BO3)4}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2016}, volume = {42}, number = {12}, pages = {1112-1119}, doi = {http://dx.doi.org/10.1063/1.4973009} }
Eremenko V., Sirenko A., Sirenko V., Dolbin A., Gospodarev I., Syrkin E., Feodosyev S., Bondar I., Minakova K.	Role of acoustic phonons in the negative thermal expansion of layered structures and nanotubes based on them [Abstract] [BibTeX]	2016	Low Temperature Physics Vol. 42(5), pp. 401-410	DOI
Abstract: Calculations on a microscopic level are used to explain the experimentally observed negative linear thermal expansion along some directions in a number of crystalline compounds with complicated lattices and anisotropic interactions between atoms. Anomalies in the temperature dependence of the coefficient of linear thermal expansion are analyzed in layered crystals made up of monatomic layers (graphite and graphene nanofilms) and multilayer "sandwiches" (transition metal dichalcogenides), in multilayered crystal structures such as high-temperature superconductors where the anisotropy of the interatomic interactions is not conserved in the long-range order, and in graphene nanotubes. The theoretical calculations are compared with data from x-ray, neutron diffraction, and dilatometric measurements.
BibTeX: @article{Eremenko2016401, author = {Eremenko, V.V. and Sirenko, A.F. and Sirenko, V.A. and Dolbin, A.V. and Gospodarev, I.A. and Syrkin, E.S. and Feodosyev, S.B. and Bondar, I.S. and Minakova, K.A.}, title = {Role of acoustic phonons in the negative thermal expansion of layered structures and nanotubes based on them}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2016}, volume = {42}, number = {5}, pages = {401-410}, doi = {http://dx.doi.org/10.1063/1.4951701} }
Eremenko V., Sirenko V., Gospodarev I., Syrkin E., Feodosyev S., Bondar I., Saxena S., Feher A., Minakova K.	Effect of step-edge on spectral properties and planar stability of metallic bigraphene [Abstract] [BibTeX]	2016	Low Temperature Physics Vol. 42(2), pp. 99-105	DOI
Abstract: Phonon and electron spectra of metallic bigraphene are analyzed in the presence of step-edge crystal imperfection. Different geometries of step-edge are considered. The dynamic planar stability of the considered structure is proved for temperatures above the ambient. The number of phonon states is shown to grow near the K-point of the first Brillouin zone, compared to pristine graphene. It is found, that this type of defects causes substantially nonuniform distribution of electron states and the pronounced increase in the number of states with energies close to Fermi energy can be expected in electron spectrum of the graphene-based compounds. The performed calculations are in good agreement with inelastic neutron, x-ray and Raman measurements.
BibTeX: @article{Eremenko201699, author = {Eremenko, V.V. and Sirenko, V.A. and Gospodarev, I.A. and Syrkin, E.S. and Feodosyev, S.B. and Bondar, I.S. and Saxena, S.S. and Feher, A. and Minakova, K.A.}, title = {Effect of step-edge on spectral properties and planar stability of metallic bigraphene}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2016}, volume = {42}, number = {2}, pages = {99-105}, doi = {http://dx.doi.org/10.1063/1.4941004} }
Grechnev G., Logosha A., Panfilov A., Zhuravleva I., Lyogenkaya A.	Features of the electronic structure of the ternary superconductors RRh4B4 (R = Y, Lu) [Abstract] [BibTeX]	2016	Low Temperature Physics Vol. 42(1), pp. 26-30	DOI
Abstract: The electronic structure and a number of thermodynamic characteristics of the ternary RRh4B4 (R = Y, Lu) systems of superconductors in the normal phase are calculated from first principles. The electronic states and interactions responsible for the superconducting and magnetic properties of these systems are analyzed. It is found that the Fermi level in the compounds YRh4B4 and LuRh4B4 is immediately adjacent to a peak in the density of electronic states and about 1 eV above a pseudogap in the electronic spectrum. The existence of a number of groups of quasi-degenerate electronic states with low effective masses near the Fermi level is revealed. These states may be the cause of a significant diamagnetic contribution of the conduction electrons to the magnetic susceptibility and may be responsible for the strong temperature dependence of the susceptibility in the rhodium borides.
BibTeX: @article{Grechnev201626, author = {Grechnev, G.E. and Logosha, A.V. and Panfilov, A.S. and Zhuravleva, I.P. and Lyogenkaya, A.A.}, title = {Features of the electronic structure of the ternary superconductors RRh4B4 (R = Y, Lu)}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2016}, volume = {42}, number = {1}, pages = {26-30}, doi = {http://dx.doi.org/10.1063/1.4940344} }
Lyogenkaya A., Grechnev G., Kotlyar O., Panfilov A., Gnezdilov V.	Electronic structure and magnetic properties of FeTe, BiFeO₃, SrFe₁₂O₁₉ and SrCoTiFe₁₀O₁₉ compounds [Abstract] [BibTeX]	2016	Ukrainian Journal of Physics Vol. 61(6), pp. 523-530	DOI
Abstract: The electronic energy structures and magnetic properties of iron-based compounds with group VI elements (FeTe, BiFeO3, SrFe12O19 and SrCoTiFe10O19) are studied using the density functional theory (DFT) methods. Manifestations of different types of chemical bonds in magnetism of these compounds are studied theoretically. Calculations of electronic structures of these systems are performed, by using the generalized gradient approximation (GGA) for the description of the exchange and correlation effects within DFT. For SrFe12O19 and SrCoTiFe10O19 hexaferrites, the GGA + U method is also employed to deal with strongly correlated 3d-electrons. The calculations have revealed distinctive features of the electronic structure of the investigated iron-based compounds with strongly correlated 3d-electrons, which can be responsible for their peculiar structural and magnetic properties.
BibTeX: @article{Lyogenkaya2016523, author = {Lyogenkaya, A.A. and Grechnev, G.E. and Kotlyar, O.V. and Panfilov, A.S. and Gnezdilov, V.P.}, title = {Electronic structure and magnetic properties of FeTe, BiFeO₃, SrFe₁₂O₁₉ and SrCoTiFe₁₀O₁₉ compounds}, journal = {Ukrainian Journal of Physics}, publisher = {National Academy of Sciences of Ukraine}, year = {2016}, volume = {61}, number = {6}, pages = {523-530}, doi = {http://dx.doi.org/10.15407/ujpe61.06.0523} }
Ozhigov L., Mitrofanov A., Desnenko V., Shramchenko S., Кrainyuk Y., Ribalchenko N.	Microstructure and coercimetry of welded joint of collector joining with steam generator body on power-generating unit of WWER-1000 [Abstract] [BibTeX]	2016	Problems of Atomic Science and Technology Vol. 101(1), pp. 61-64	URL
Abstract: The results of research to identify the correlation between the microstructure of the weld metal laminated and coercive force are presented. It is shown that for different phases of the weld microstructure (fine-grained and columnar structure) there are significant changes in the measured magnetic parameters. This method for determining the interdependencies Hcand deformation texture in a metal can be regarded as promising for the control structure of the metal structures.
BibTeX: @article{Ozhigov201661, author = {Ozhigov, L.S. and Mitrofanov, A.S. and Desnenko, V.A. and Shramchenko, S.V. and Кrainyuk, Y. and Ribalchenko, N.D.}, title = {Microstructure and coercimetry of welded joint of collector joining with steam generator body on power-generating unit of WWER-1000}, journal = {Problems of Atomic Science and Technology}, publisher = {National Science Center, Kharkov Institute of Physics and Technology}, year = {2016}, volume = {101}, number = {1}, pages = {61-64}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84958554994&partnerID=40&md5=fd32905109ff4fa02adcf45fac01239a} }
Polishchuk D., Tovstolytkin A., Fertman E., Desnenko V., Kravchyna O., Khalyavin D., Salak A., Anders A., Feher A.	Charge ordering in Nd2/3Ca1/3MnO3: ESR and magnetometry study [Abstract] [BibTeX]	2016	Journal of Magnetism and Magnetic Materials Vol. 410, pp. 109-115	DOI
Abstract: The evolution of magnetic and electric properties of the narrow-band manganite Nd2/3Ca1/3MnO3 was studied by the electron-spin resonance (ESR), static magnetic field (dc) and resistivity techniques in the temperature range of 100-380 K. It was found that below the charge ordering temperature, TCO≈212 K, the compound is a mixture of the charge ordered and charge disordered phases in varying proportions depending on the temperature. The exchange phase process, when the amount of the charge ordered phase increases under cooling, while the amount of the charge disordered phase decreases is the most intense between ∼220 K and 180 K. At low temperatures, T<160 K, the charge ordered to the charge disordered phase ratio is about 4:1, which is in excellent agreement with previous neutron diffraction data. Both a sharp decrease of the magnetic susceptibility and a huge resistivity increase are evident of the weakening of ferromagnetic correlations and suppression of the double exchange interaction across the charge ordering due to the localization of the charge carriers.
BibTeX: @article{Polishchuk2016109, author = {Polishchuk, D.M. and Tovstolytkin, A.I. and Fertman, E.L. and Desnenko, V.A. and Kravchyna, O. and Khalyavin, D.D. and Salak, A.N. and Anders, A.G. and Feher, A.}, title = {Charge ordering in Nd2/3Ca1/3MnO3: ESR and magnetometry study}, journal = {Journal of Magnetism and Magnetic Materials}, publisher = {Elsevier B.V.}, year = {2016}, volume = {410}, pages = {109-115}, doi = {http://dx.doi.org/10.1016/j.jmmm.2016.03.022} }
Prikhna T., Eisterer M., Chaud X., Weber H., Habisreuther T., Moshchil V., Kozyrev A., Shapovalov A., Gawalek W., Wu M., Litzkendorf D., Goldacker W., Sokolovsky V., Shaternik V., Rabier J., Joulain A., Grechnev G., Boutko V., Gusev A., Shaternik A., Barvitskiy P.	Pinning and trapped field in MgB2- and MT-YBaCuO bulk superconductors manufactured under pressure [Abstract] [BibTeX]	2016	Journal of Physics: Conference Series Vol. 695(1), pp. 012001	DOI
Abstract: The relevant pinning centers of Abrikosov vortices in MgB2-based materials are oxygen-enriched Mg-B-O inclusions or nanolayers and inclusions of MgBx (x>4) phases. The high critical current densities, j c, of 106 and 103A/cm2 at 1 and 8.5 T, respectively, at 20 K can be achieved in polycrystalline materials (prepared at 2 GPa) containing a large amount of admixed oxygen. Besides, oxygen can be incorporated into the MgB2 structure in small amounts (MgB1.5O0.5), which is supported by Auger studies and calculations of the DOS and the binding energy. The j c of melt textured YBa2Cu3O7-δ (or Y123)-based superconductors (MT-YBaCuO) depends not only on the perfectness of texture and the amount of oxygen in the Y123 structure, but also on the density of twins and micro-cracks formed during the oxygenation (due to shrinking of the c-lattice parameter). The density of twins and microcracks increases with the reduction of the distance between Y2BaCuO5 (Y211) inclusions in Y123. At 77 K jc=8•104 A/cm2 in self-field and jc=103 A/cm2 at 10 T were found in materials oxygenated at 16 MPa for 3 days with a density of twins of 2235 per μm (thickness of the lamellae: 45-30 nm) and a density of micro-cracks of 200280 per mm. Pinning can occur at the points of intersection between the Y123 twin planes and the Y211 inclusions. MTYBaCuO at 77 K can trap 1.4 T (38×38×17 mm, oxygenated at 0.1 MPa for 20 days) and 0.8 T (16 mm in diameter and 10 mm thick with 0.45 mm holes oxygenated at 10 MPa for 53 h). The sensitivity of MgB2 to magnetic field variations (flux jumps) complicates estimates of the trapped field. At 20 K 1.8 T was found for a block of 30 mm in diameter and a thickness of 7.5 mm and 1.5 T (if the magnetic field was increased at a rate of 0.1 T) for a ring with dimensions 24×18 mm and a thickness of 8 mm.
BibTeX: @article{Prikhna2016, author = {Prikhna, T. and Eisterer, M. and Chaud, X. and Weber, H.W. and Habisreuther, T. and Moshchil, V. and Kozyrev, A. and Shapovalov, A. and Gawalek, W. and Wu, M. and Litzkendorf, D. and Goldacker, W. and Sokolovsky, V. and Shaternik, V. and Rabier, J. and Joulain, A. and Grechnev, G. and Boutko, V. and Gusev, A. and Shaternik, A. and Barvitskiy, P.}, title = {Pinning and trapped field in MgB2- and MT-YBaCuO bulk superconductors manufactured under pressure}, journal = {Journal of Physics: Conference Series}, publisher = {Institute of Physics Publishing}, year = {2016}, volume = {695}, number = {1}, pages = {012001}, doi = {http://dx.doi.org/10.1088/1742-6596/695/1/012001} }
Prikhna T., Shapovalov A., Grechnev G., Boutko V., Gusev A., Kozyrev A., Belogolovskiy M., Moshchil V., Sverdun V.	Formation of nanostructure in magnesium diboride based materials with high superconducting characteristics [Abstract] [BibTeX]	2016	Low Temperature Physics Vol. 42(5), pp. 380-394	DOI
Abstract: The paper presents an analysis of the properties of bulk superconducting magnesium diboride-based materials obtained by heating at high quasi-hydrostatic pressures (1-2 GPa), hot pressing (30 MPa), spark plasma sintering (16-96 MPa) and loose powder sintering. It is shown that the optimization of impurity distribution in MgB2 can be achieved by varying the synthesis conditions and introducing dopants. In particular, polycrystalline MgB2 materials synthesized at 2 GPa and containing a high amount of impurity oxygen demonstrates high critical current densities (106 and 103 A/cm2 at 20 K in magnetic fields of 1 and 8.5 T, respectively). It is found that the oxygen impurities are mainly localized in nanolayers or nanoinclusions, homogeneously distributed in the matrix. They act as pinning centers, while the MgB2 matrix also contains small amounts of dissolved oxygen. Impurity or intentionally added carbon entering the magnesium diboride structure leads to an increase in the critical magnetic fields up to Bc2 (22 K) = 15 T and Birr (18.5 K) = 15 T. The results of ab initio calculations of the electronic structure and stability of the magnesium diboride compounds with partial oxygen or carbon substitution for boron show that it is energetically favorable for carbon to distribute homogeneously in MgB2 structure, while oxygen atoms replace boron pairwise in neighboring positions or form zigzag chains.
BibTeX: @article{Prikhna2016380, author = {Prikhna, T.A. and Shapovalov, A.P. and Grechnev, G.E. and Boutko, V.G. and Gusev, A.A. and Kozyrev, A.V. and Belogolovskiy, M.A. and Moshchil, V.E. and Sverdun, V.B.}, title = {Formation of nanostructure in magnesium diboride based materials with high superconducting characteristics}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2016}, volume = {42}, number = {5}, pages = {380-394}, doi = {http://dx.doi.org/10.1063/1.4952985} }
Troyanchuk I., Bushinsky M., Chobot A., Mantytskaya O., Tereshko N., Chobot G., Sirenko V., Eremenko V.	Magnetic properties of the multiferroics Bi1-xCaxFe1-xMnxO3 and Bi1-xCaxFe1-xTixO3 [Abstract] [BibTeX]	2016	Low Temperature Physics Vol. 42(12), pp. 1122-1125	DOI
Abstract: This is a study of the crystalline structure and magnetic properties of the multiferroics Bi1-xCaxFe1-xMexO3 (Me=Mn, Ti). It is shown that Mn and Ti are in a quadrivalent state and the oxygen stoichiometry is conserved. The Me=Mn series undergoes a conversion at x=0.19 from a polar rhombohedral phase (R3c) to a nonpolar orthorhombic phase (Pnma). A similar transition in the Me=Ti series was observed at x=0.25. In both series, the polar phase (x≥0.1) is weakly ferromagnetic. The spontaneous magnetization of the titanium series, however, exceeds that of the manganese series by more than a factor of three, despite the fact that Ti4+ is a diamagnetic ion. The residual magnetization of the titanium series decreases with rising temperature, while that of the manganese series increases anomalously within the interval 0.1≤x≤0.22. This behavior of the magnetic properties of the manganese series is explained by the extremely high sensitivity of the magnetic anisotropy to changes in the parameters of the crystal lattice, which leads to spin reversal.
BibTeX: @article{Troyanchuk20161122, author = {Troyanchuk, I.O. and Bushinsky, M.V. and Chobot, A.N. and Mantytskaya, O.S. and Tereshko, N.V. and Chobot, G.M. and Sirenko, V.A. and Eremenko, V.V.}, title = {Magnetic properties of the multiferroics Bi1-xCaxFe1-xMnxO3 and Bi1-xCaxFe1-xTixO3}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2016}, volume = {42}, number = {12}, pages = {1122-1125}, doi = {http://dx.doi.org/10.1063/1.4973007} }
Zentková M., Mihalik M., Mihalik M. J., Sirenko V., Eremenko V., Balbashov A., Kvetková L., Koval V., Výrostková A., Briančin J., Wang X., Kamenev K.	Preparation and physical properties of M-type hexaferrite SrCo2Ti2Fe8O19 [Abstract] [BibTeX]	2016	Ferroelectrics Vol. 499(1), pp. 1-8	DOI
Abstract: ABSTRACT: Measurements of Raman spectra, dielectric constant and magnetization were performed on M-type hexaferrite SrCo2Ti2Fe8O19 single crystal, which was grown by travelling solvent method in an optical furnace. The Raman spectra measurements at room temperature revealed that main Raman modes, which are associated with the bipyramid FeO5, octahedra Fe(4)O6 and Fe(5)O6 as well with mixed octahedral vibration all with A1 g symmetry, shift monotonously to higher wave numbers. In the low-frequency region (<10 kHz), permittivity rapidly decreases with increasing frequency, exhibiting a typical characteristic of Maxwell-Wagner type relaxation. The relaxation peak in dielectric losses centred on 100 kHz can be attributed to ionic relaxation processes caused by multiple valence states of iron ion (Fe2+ and Fe3+). M-type hexaferrite SrCo2Ti2Fe8O19 orders magnetically at 768 K and undergoes order-to-order magnetic phase transition at 380 K. Magnetic properties are almost isotropic around room temperatures with very low hysteresis having coercive field with induction lower than 3×10−3 T and with remnant magnetization lower than 0.17 μB/f.u. for magnetic fields applied along main crystallographic directions.
BibTeX: @article{Zentková20161, author = {Zentková, M. and Mihalik, M. and Mihalik, M., Jr. and Sirenko, V. and Eremenko, V.V. and Balbashov, A.M. and Kvetková, L. and Koval, V. and Výrostková, A. and Briančin, J. and Wang, X. and Kamenev, K.}, title = {Preparation and physical properties of M-type hexaferrite SrCo2Ti2Fe8O19}, journal = {Ferroelectrics}, publisher = {Taylor and Francis Inc.}, year = {2016}, volume = {499}, number = {1}, pages = {1-8}, doi = {http://dx.doi.org/10.1080/00150193.2016.1170565} }
Zhuravleva I., Grechnev G., Panfilov A., Lyogenkaya A., Kotlyar O., Fedorchenko A., Feher A.	Electronic structure and magnetic properties of RT4Al8 (R = Sc, Y, La, Lu; T = Fe, Mn, Cr) compounds. Hydrostatic pressure effects [Abstract] [BibTeX]	2016	Low Temperature Physics Vol. 42(6), pp. 458-465	DOI
Abstract: We present results of theoretical and experimental studies of the electronic structure and magnetic properties of RFe4Al8, RMn4Al8, and RCr4Al8 compounds with nonmagnetic elements R = Sc, Y, La, and Lu. The electron spectrum and field induced magnetic moment, as well as their dependences on the unit cell volume, are calculated for the paramagnetic phase of the RT4Al8 systems. The calculations are supplemented by measurements of the magnetic susceptibility of representative RT4Al8 compounds as a function of temperature and hydrostatic pressure.
BibTeX: @article{Zhuravleva2016458, author = {Zhuravleva, I.P. and Grechnev, G.E. and Panfilov, A.S. and Lyogenkaya, A.A. and Kotlyar, O.V. and Fedorchenko, A.V. and Feher, A.}, title = {Electronic structure and magnetic properties of RT4Al8 (R = Sc, Y, La, Lu; T = Fe, Mn, Cr) compounds. Hydrostatic pressure effects}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2016}, volume = {42}, number = {6}, pages = {458-465}, doi = {http://dx.doi.org/10.1063/1.4954784} }
Zvyagina G., Zhekov K., Bilych I., Kolodyazhnaya M., Zvyagin A., Bludov A., Pashchenko V., Gudim I.	Low-temperature magnetic phase transitions in the multiferroic Nd0.9Dy0.1Fe3(BO3)4. Part 1. Transitions induced by magnetic fields directed along the trigonal symmetry axis. Spontaneous transitions with temperature changes [Abstract] [BibTeX]	2016	Low Temperature Physics Vol. 42(4), pp. 273-279	DOI
Abstract: The elastic and magnetic characteristics of single-crystal Nd0.9Dy0.1Fe3(BO3)4 are studied at low temperatures in zero magnetic field and in external fields H\|\|C3. The temperature dependences of the acoustic mode velocities and the magnetic susceptibility manifest a transition of the magnetic subsystem into a magnetically ordered state and two successive, spontaneous spin-reorientation phase transitions. The possibility of a spontaneous transition into an incommensurate (spiral) magnetic phase in the crystal is discussed. It is shown that an external magnetic field directed along the trigonal axis of the crystal induces a sequence of spin-reorientation phase transitions. An H-T phase diagram (H\|\|C3) is constructed for this compound.
BibTeX: @article{Zvyagina2016273, author = {Zvyagina, G.A. and Zhekov, K.R. and Bilych, I.V. and Kolodyazhnaya, M.P. and Zvyagin, A.A. and Bludov, A.N. and Pashchenko, V.A. and Gudim, I.A.}, title = {Low-temperature magnetic phase transitions in the multiferroic Nd0.9Dy0.1Fe3(BO3)4. Part 1. Transitions induced by magnetic fields directed along the trigonal symmetry axis. Spontaneous transitions with temperature changes}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2016}, volume = {42}, number = {4}, pages = {273-279}, doi = {http://dx.doi.org/10.1063/1.4947480} }
Eremenko V., Sirenko V., Gospodarev I., Syrkin E., Feodosyev S., Bondar I., Minakova K.	Anisotropic behavior and inhomogeneity of atomic local densities of states in graphene with vacancy groups [Abstract] [BibTeX]	2016	Journal of Science: Advanced Materials and Devices Vol. 1(2), pp. 167-173	DOI
Abstract: The electron local density of states (LDOS) are calculated for graphene with isolated vacancies, divacancies and vacancy group of four nearest-neighbor vacancies. A strong anisotropy of behavior of LDOS near Fermi level is demonstrated for atoms near defect. Effect of next-to-nearest neighbor interaction on the properties of graphene with vacancies is established.
BibTeX: @article{Eremenko2016167, author = {Eremenko, V.V. and Sirenko, V.A. and Gospodarev, I.A. and Syrkin, E.S. and Feodosyev, S.B. and Bondar, I.S. and Minakova, K.A.}, title = {Anisotropic behavior and inhomogeneity of atomic local densities of states in graphene with vacancy groups}, journal = {Journal of Science: Advanced Materials and Devices}, publisher = {Elsevier B.V.}, year = {2016}, volume = {1}, number = {2}, pages = {167-173}, doi = {http://dx.doi.org/10.1016/j.jsamd.2016.06.011} }
Arhipov P., Tkachenko S., Gerasymov I., Sidletskiy O., Hubenko K., Vasyukov S., Shiran N., Baumer V., Mateychenko P., Fedorchenko A., Zorenko Y., Zhydachevskii Y., Lebbou K., Korjik M.	Growth and characterization of large CeAlO₃ perovskite crystals [Abstract] [BibTeX]	2015	Journal of Crystal Growth Vol. 430, pp. 116-121	DOI
Abstract: This study is focused on obtaining large CeAlO₃ single crystals. Using Czochralski and Edge-Defined Film Fed Growth techniques, crystals of length up to 130 mm were obtained. The crystals belong to the tetragonal low temperature modification of CeAlO₃, space group P4/mmm, a=3.7669 Å, c=3.7967 Å. Density and crystallographic parameters as well as some optical, luminescence and magnetic properties of CeAlO₃ were studied. The crystals demonstrate rather bright luminescence under UV-excitation, while no luminescence has been registered under X-rays. Ceramic and single crystalline CeAlO₃ samples demonstrate p-type conductivity and promising paramagnetic properties.
BibTeX: @article{Arhipov2015116, author = {Arhipov, P. and Tkachenko, S. and Gerasymov, I. and Sidletskiy, O. and Hubenko, K. and Vasyukov, S. and Shiran, N. and Baumer, V. and Mateychenko, P. and Fedorchenko, A. and Zorenko, Y. and Zhydachevskii, Y. and Lebbou, K. and Korjik, M.}, title = {Growth and characterization of large CeAlO₃ perovskite crystals}, journal = {Journal of Crystal Growth}, publisher = {Elsevier}, year = {2015}, volume = {430}, pages = {116-121}, doi = {http://dx.doi.org/10.1016/j.jcrysgro.2015.08.025} }
Baranovskiy A., Grechnev A.	Electronic structure and exchange interactions in GdB4 [Abstract] [BibTeX]	2015	Journal of Magnetism and Magnetic Materials Vol. 375, pp. 96-99	DOI
Abstract: The electronic structure of the antiferromagnetic Shastry-Sutherland compound GdB4 has been analyzed with density functional theory and the all-electron full-potential linearized augmented-plane wave (FP-LAPW) code. Different magnetic configurations, including the realistic dimer one, have been considered. The exchange interactions were found to be J1/kB=-12K and J2/kB=-2-0.8K, where, J1 and J2 are the diagonal exchange interaction and the exchange interaction along the edges of a square, respectively.
BibTeX: @article{Baranovskiy201596, author = {Baranovskiy, A. and Grechnev, A.}, title = {Electronic structure and exchange interactions in GdB4}, journal = {Journal of Magnetism and Magnetic Materials}, publisher = {Elsevier}, year = {2015}, volume = {375}, pages = {96-99}, doi = {http://dx.doi.org/10.1016/j.jmmm.2014.09.032} }
Fertman E., Syrkin E., Lykah V., Desnenko V., Beznosov A., Pal-Val P., Pal-Val L., Fedorchenko A., Khalyavin D., Feher A.	Structural phase transition in La_2/3Ba_1/3MnO₃ perovskite: Elastic, magnetic, and lattice anomalies and microscopic mechanism [Abstract] [BibTeX]	2015	AIP Advances Vol. 5(7), pp. 077189	DOI
Abstract: The temperature dependences of the elastic and magnetic properties of polycrystalline perovskite manganite La_2/3Ba_1/3MnO₃ were studied using ultrasonic and SQUID magnetometer techniques. The minimum of the temperature-dependent sound velocity v(T) and corresponding maximum of the decrement δ(T) were found in the vicinity of the structural phase transition R 3 → I m m a at T_s ∼ 200 K. Large alterations of v and δ indicate a structural phase transition of the soft mode type. A high sensitivity of dc magnetization to a low uniaxial pressure caused by the softening was found in the T_s region. A negative value of the linear thermal expansion coefficient along one of the crystallographic axis was found in the Imma phase near T_s. The proposed microscopic mechanism explains the appearance of the soft mode in the vicinity of the structural phase transition temperature associated with the displacement of the manganese atom from the center of the oxygen octahedron.
BibTeX: @article{Fertman2015, author = {Fertman, E. and Syrkin, E. and Lykah, V. and Desnenko, V. and Beznosov, A. and Pal-Val, P. and Pal-Val, L. and Fedorchenko, A. and Khalyavin, D. and Feher, A.}, title = {Structural phase transition in La_2/3Ba_1/3MnO₃ perovskite: Elastic, magnetic, and lattice anomalies and microscopic mechanism}, journal = {AIP Advances}, publisher = {American Institute of Physics Inc.}, year = {2015}, volume = {5}, number = {7}, pages = {077189}, doi = {http://dx.doi.org/10.1063/1.4928075} }
Fertman E., Fedorchenko A., Kotlyar A., Desnenko V., Čižmár E., Baran A., Khalyavin D., Salak A., Shvartsman V., Feher A.	Exchange bias phenomenon in (Nd1-xYx)2/3Ca1/3MnO3 (x = 0, 0.1) perovskites [Abstract] [BibTeX]	2015	Low Temperature Physics Vol. 41(12), pp. 1001-1005	DOI
Abstract: Exchange bias phenomenon, evident of antiferromagnetic-ferromagnetic phase segregation state, has been observed in (Nd1-xYx)2/3Ca1/3MnO3 (x = 0, 0.1) compounds at low temperatures. A contribution to the total magnetization of the compounds due to the ferromagnetic phase has been evaluated. It has been found that yttrium doping leads to the growth of the ferromagnetic phase fraction. The ferromagnetic phase in the doped compound has a lower coercivity Hc and more rectangular form of the hysteresis loop. The values of the exchange bias field HEB and coercivity are found to be strongly dependent on the cooling magnetic field Hcool. In sufficiently high magnetic fields, Hcool > 5 kOe, HEB in the doped compound is about twice as low as in the parent compound. This difference is attributed to a lower exchange interaction and higher saturation magnetization of the ferromagnetic phase in (Nd0.9Y0.1)2/3Ca1/3MnO3.
BibTeX: @article{Fertman20151001, author = {Fertman, E.L. and Fedorchenko, A.V. and Kotlyar, A.V. and Desnenko, V.A. and Čižmár, E. and Baran, A. and Khalyavin, D.D. and Salak, A.N. and Shvartsman, V.V. and Feher, A.}, title = {Exchange bias phenomenon in (Nd1-xYx)2/3Ca1/3MnO3 (x = 0, 0.1) perovskites}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2015}, volume = {41}, number = {12}, pages = {1001-1005}, doi = {http://dx.doi.org/10.1063/1.4936671} }
Gaydamak T., Gudim I., Zvyagina G., Bilych I., Burma N., Zhekov K., Fil V.	Magnetopiezoelectric effect and magnetocapacitance in SmFe3(BO3)4 [Abstract] [BibTeX]	2015	Physical Review B - Condensed Matter and Materials Physics Vol. 92(21), pp. 214428	DOI
Abstract: A giant magnetopiezoelectric effect has been revealed in samarium ferroborate. The effective piezomodulus is increased more than twice in the antiferromagnetic phase and it is reduced by a high magnetic field. The nature of the effect is in the joint contribution of both magnetoelectric and magnetoelastic interactions. The evolu-tion of this contribution in the magnetic field is caused by the growth of the magnetic energy including the spin reorientation. Additional data concerning the behavior of the high-frequency magnetocapacitance have been obtained. The parameters of magnetoelectric and magnetoelastic couplings and the magnetic anisotropy constant in the basal plane have been determined.
BibTeX: @article{Gaydamak2015, author = {Gaydamak, T.N. and Gudim, I.A. and Zvyagina, G.A. and Bilych, I.V. and Burma, N.G. and Zhekov, K.R. and Fil, V.D.}, title = {Magnetopiezoelectric effect and magnetocapacitance in SmFe3(BO3)4}, journal = {Physical Review B - Condensed Matter and Materials Physics}, publisher = {American Physical Society}, year = {2015}, volume = {92}, number = {21}, pages = {214428}, doi = {http://dx.doi.org/10.1103/PhysRevB.92.214428} }
Gaydamak T., Gudim I., Zvyagina G., Bilych I., Burma N., Zhekov K., Fil V.	Elastic and piezoelectric moduli of Nd and Sm ferroborates [Abstract] [BibTeX]	2015	Low Temperature Physics Vol. 41(8), pp. 614-618	DOI
Abstract: The sound speeds are measured and the elastic and piezoelectric moduli are calculated for single crystal NdFe₃(BO₃)₄ and SmFe₃(BO₃)₄. These compounds are characterized by enhanced rigidity in the base plane with respect to stress-strain deformations and by a rather strong piezoelectric effect.
BibTeX: @article{Gaydamak2015614, author = {Gaydamak, T.N. and Gudim, I.A. and Zvyagina, G.A. and Bilych, I.V. and Burma, N.G. and Zhekov, K.R. and Fil, V.D.}, title = {Elastic and piezoelectric moduli of Nd and Sm ferroborates}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2015}, volume = {41}, number = {8}, pages = {614-618}, doi = {http://dx.doi.org/10.1063/1.4929719} }
Grechnev G., Lyogenkaya A., Panfilov A., Logosha A., Kotlyar O., Gnezdilov V., Makarova I., Chareev D., Mitrofanova E.	Features of the electron structure of FeTe compounds [Abstract] [BibTeX]	2015	Low Temperature Physics Vol. 41(12), pp. 990-995	DOI
Abstract: A theoretical and experimental study of the electron structure and nature of the chemical bonds in FeTe compounds in antiferromagnetic (AFM) and paramagnetic phases. It is established that the nature of the chemical bonds is mainly metallic, and the presence of covalent bonds Fe-Te and Te-Te helps to stabilize the structural distortions of the tetragonal phase of FeTe in the low-temperature region. It is found that the bicollinear AFM structure corresponds to the ground state of the FeTe compound and the calculated value of the magnetic moment MFe = -2.4μB is in good agreement with the data from neutron diffraction measurements. At the same time, the Fermi surface (FS) of the low-temperature AFM phase is radically different from the FS of the paramagnetic FeTe. Reconstructing the FS can lead to a sign change of the Hall coefficient observed in FeTe. The calculation results serve as evidence of the fact that the electron structures and magnetic properties of FeTe are well-described by the model of itinerant d-electrons and the density functional theory (DFT-GGA).
BibTeX: @article{Grechnev2015990, author = {Grechnev, G.E. and Lyogenkaya, A.A. and Panfilov, A.S. and Logosha, A.V. and Kotlyar, O.V. and Gnezdilov, V.P. and Makarova, I.P. and Chareev, D.A. and Mitrofanova, E.S.}, title = {Features of the electron structure of FeTe compounds}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2015}, volume = {41}, number = {12}, pages = {990-995}, doi = {http://dx.doi.org/10.1063/1.4938519} }
Karpinsky D., Troyanchuk I., Silibin M., Gavrilov S., Bushinsky M., Sikolenko V., Sirenko V., Tebbens D.	Crystal structure and magnetic exchange in La1-2xSr2xMn1-xSbxO3 (x ≤ 0.2) solid solutions [Abstract] [BibTeX]	2015	Low Temperature Physics Vol. 41(12), pp. 1006-1010	DOI
Abstract: The crystal structure and magnetic properties of the stoichiometric compounds La1-2xSr2xMn1-xSbxO3 (0.1 ≤ x ≤ 0.2) with manganese ions in the 3+ oxidation state are studied. These compounds exhibit rhombohedral structure at room temperatures, which transforms upon cooling into an orthorhombic structure without any signature of orbital ordering. The compounds with x ≤ 0.2 reveal a ferromagnetic ordering; their magnetization decreases with increasing the concentration of substitution ions. It is suggested that the observed ferromagnetism originates from the breakdown of orbital ordering and significant hybridization between the eg orbitals of Mn3+ and 2p orbitals of oxygen.
BibTeX: @article{Karpinsky20151006, author = {Karpinsky, D.V. and Troyanchuk, I.O. and Silibin, M.V. and Gavrilov, S.A. and Bushinsky, M.V. and Sikolenko, V. and Sirenko, V. and Tebbens, D.}, title = {Crystal structure and magnetic exchange in La1-2xSr2xMn1-xSbxO3 (x ≤ 0.2) solid solutions}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2015}, volume = {41}, number = {12}, pages = {1006-1010}, doi = {http://dx.doi.org/10.1063/1.4937365} }
Khalyavin D., Salak A., Lopes A., Olekhnovich N., Pushkarev A., Radyush Y., Fertman E., Desnenko V., Fedorchenko A., Manuel P., Feher A., Vieira J., Ferreira M.	Magnetic structure of an incommensurate phase of La-doped BiFe0.5Sc0.5 O3: Role of antisymmetric exchange interactions [Abstract] [BibTeX]	2015	Physical Review B - Condensed Matter and Materials Physics Vol. 92(22), pp. 224428	DOI
Abstract: A 20% substitution of Bi with La in the perovskite Bi1-xLaxFe0.5Sc0.5O3 system obtained under high-pressure and high-temperature conditions has been found to induce an incommensurately modulated structural phase. The room-temperature x-ray and neutron powder diffraction patterns of this phase were successfully refined using the Imma(0,0,γ)s00 superspace group (γ=0.534(3)) with the modulation applied to Bi/La and oxygen displacements. The modulated structure is closely related to the prototype antiferroelectric structure of PbZrO3 which can be considered as the lock-in variant of the latter with γ=0.5. Below TN∼220 K, the neutron diffraction data provide evidence for a long-range G-type antiferromagnetic ordering commensurate with the average Imma structure. Based on a general symmetry consideration, we show that the direction of the spins is controlled by the antisymmetric exchange imposed by the two primary structural distortions, namely oxygen octahedral tilting and incommensurate atomic displacements. The tilting is responsible for the onset of a weak ferromagnetism, observed in magnetization measurements, whereas the incommensurate displacive mode is dictated by the symmetry to couple a spin-density wave. The obtained results demonstrate that antisymmetric exchange is the dominant anisotropic interaction in Fe3+-based distorted perovskites with a nearly quenched orbital degree of freedom.
BibTeX: @article{Khalyavin2015, author = {Khalyavin, D.D. and Salak, A.N. and Lopes, A.B. and Olekhnovich, N.M. and Pushkarev, A.V. and Radyush, Y.V. and Fertman, E.L. and Desnenko, V.A. and Fedorchenko, A.V. and Manuel, P. and Feher, A. and Vieira, J.M. and Ferreira, M.G.S.}, title = {Magnetic structure of an incommensurate phase of La-doped BiFe0.5Sc0.5 O3: Role of antisymmetric exchange interactions}, journal = {Physical Review B - Condensed Matter and Materials Physics}, publisher = {American Physical Society}, year = {2015}, volume = {92}, number = {22}, pages = {224428}, doi = {http://dx.doi.org/10.1103/PhysRevB.92.224428} }
Khalyavin D., Salak A., Manuel P., Olekhnovich N., Pushkarev A., Radysh Y., Fedorchenko A., Fertman E., Desnenko V., Ferreira M.	Antisymmetric exchange in La-substituted BiFe0.5Sc0.5O3 system: Symmetry adapted distortion modes approach [Abstract] [BibTeX]	2015	Zeitschrift fur Kristallographie - Crystalline Materials Vol. 230(12), pp. 767-774	DOI
Abstract: Neutron powder diffraction measurements on the 35 % La-substituted Bi1-xLaxFe0.5Sc0.5O3 composition revealed that the samples obtained under high-pressure (6 GPa) and higherature (1500 K) conditions crystalize into a distorted perovskite structure with the orthorhombic Pnma symmetry and the unit cell parameters: ao = 5.6745(2) Å, bo = 7.9834(3) Å and co = 5.6310(2) Å. A long-range magnetic ordering takes place below 220 K and implies a G-type magnetic structure with the moments 4.10(4)μB per Fe aligned predominately along the orthorhombic c-axis. The space group representation theory using the orthorhombic symmetry yields four bi-linear coupling schemes for the magnetic order parameters imposed by antisymmetric exchange interactions. The couplings are analysed based on symmetry adapted distortion modes defined in respect of the undistorted cubic perovskite structure. The approach allows a quantitative estimation of the coupling strength. It is shown that the experimentally found spin configuration combines the magnetic order parameters coupled by the atomic displacement modes with the largest amplitudes. The results indicate that the antisymmetric exchange is the dominant anisotropic term which fully controls the direction of the Fe3+ spins in the distorted perovskite lattice.
BibTeX: @article{Khalyavin2015767, author = {Khalyavin, D.D. and Salak, A.N. and Manuel, P. and Olekhnovich, N.M. and Pushkarev, A.V. and Radysh, Y.V. and Fedorchenko, A.V. and Fertman, E.L. and Desnenko, V.A. and Ferreira, M.G.S.}, title = {Antisymmetric exchange in La-substituted BiFe0.5Sc0.5O3 system: Symmetry adapted distortion modes approach}, journal = {Zeitschrift fur Kristallographie - Crystalline Materials}, publisher = {Walter de Gruyter GmbH}, year = {2015}, volume = {230}, number = {12}, pages = {767-774}, doi = {http://dx.doi.org/10.1515/zkri-2015-1873} }
Mihalik M., Sirenko V., Balbashov A., Eremenko V., Mihalik M., Zentková M.	The Magnetic Properties of Single Crystal SrCo2Ti2Fe8O19 Compound [Abstract] [BibTeX]	2015	Physics Procedia Vol. 75, pp. 259-265	DOI
Abstract: We present magnetization measurements performed on a SrCo2Ti2Fe8O19 single crystal. The compound orders magnetically at 768 K and undergoes order-to-order magnetic phase transition at 380 K. Magnetic properties are almost isotropic around room temperatures with very low hysteresis with coercive field lower than 2.0(1) × 10-3 T and with remnant magnetization lower than 0.22 μB/f.u. (1.08 Am2kg-1) for magnetic fields applied along main crystallographic directions. Frequency-dependent anomalies related to complex spin dynamics of the system were observed in the temperature range from 20 to 100 K.
BibTeX: @conference{Mihalik2015259, author = {Mihalik, M. and Sirenko, V. and Balbashov, A.M. and Eremenko, V. and Mihalik, M. and Zentková, M.}, title = {The Magnetic Properties of Single Crystal SrCo2Ti2Fe8O19 Compound}, journal = {Physics Procedia}, publisher = {Elsevier B.V.}, year = {2015}, volume = {75}, pages = {259-265}, doi = {http://dx.doi.org/10.1016/j.phpro.2015.12.032} }
Ovsienko I., Len T., Matsuy L., Prylutskyy Y., Berkutov I., Andrievskii V., Komnik Y., Mirzoiev I., Grechnev G., Kolesnichenko Y., Hayn R., Scharff P.	Magnetoresistance and electrical resistivity of N-doped multi-walled carbon nanotubes at low temperatures [Abstract] [BibTeX]	2015	Physica Status Solidi (B) Basic Research Vol. 252(6), pp. 1402-1409	DOI
Abstract: The magnetoresistance and electrical resistivity of nitrogen-doped multi-walled carbon nanotubes (N-MWCNTs) were studied in the temperature range of 1.6-100.3 and 1.6-286K, respectively, using a standard four-probe technique. The possible mechanisms of the observed effects are discussed in detail.
BibTeX: @article{Ovsienko20151402, author = {Ovsienko, I.V. and Len, T.A. and Matsuy, L.Y. and Prylutskyy, Y.I. and Berkutov, I.B. and Andrievskii, V.V. and Komnik, Y.F. and Mirzoiev, I.G. and Grechnev, G.E. and Kolesnichenko, Y.A. and Hayn, R. and Scharff, P.}, title = {Magnetoresistance and electrical resistivity of N-doped multi-walled carbon nanotubes at low temperatures}, journal = {Physica Status Solidi (B) Basic Research}, publisher = {Wiley-VCH Verlag}, year = {2015}, volume = {252}, number = {6}, pages = {1402-1409}, doi = {http://dx.doi.org/10.1002/pssb.201451657} }
Panfilov A., Grechnev G., Zhuravleva I., Fedorchenko A., Muratov V.	Specific features of the magnetic properties of RB₄ (R = Ce, Sm and Yb) tetraborides. Effects of pressure [Abstract] [BibTeX]	2015	Low Temperature Physics Vol. 41(3), pp. 193-198	DOI
Abstract: The temperature dependence and the effect of pressure P up to 2 kbar on the magnetic susceptibility χ of the tetraborides SmB4 and YbB4 was studied. For the compound CeB4, the electronic structure and magnetic susceptibility were calculated from first principles as a function of the atomic volume. The results show that in the studied tetraborides, rare-earth ions (Ce4+, Sm3+ and Yb2.8+) exhibit different valence states, which determines the specific features of their magnetic properties. In particular, the obtained pressure derivatives of susceptibility dlnχ/dP for cerium, samarium and ytterbium tetraborides are -2, -0.6 and +2.7 (in units of Mbar-1), respectively, which are characteristic for the exchange-enhanced itinerant paramagnetism, Van Vleck ionic paramagnetism with a stable f-shell, and the magnetism of rare-earth ions in the intermediate valence state.
BibTeX: @article{Panfilov2015, author = {Panfilov, A.S. and Grechnev, G.E. and Zhuravleva, I.P. and Fedorchenko, A.V. and Muratov, V.B.}, title = {Specific features of the magnetic properties of RB₄ (R = Ce, Sm and Yb) tetraborides. Effects of pressure}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2015}, volume = {41}, number = {3}, pages = {193-198}, doi = {http://dx.doi.org/10.1063/1.4916067} }
Panfilov A.	Use of a pendulum magnetometer for measuring the magnetic susceptibility of solids under pressure: The compound V₄S₉Br₄ [Abstract] [BibTeX]	2015	Low Temperature Physics Vol. 41(12), pp. 1029-1033	DOI
Abstract: The construction and operating principle of a pendulum magnetometer for measuring the magnetic susceptibility of solids under high gas pressures are described. This device is distinctive in having the pendulum mounted directly in the high pressure chamber. Experimental plots of the susceptibility of the compound V4S9Br4 as a function of pressure up to 2 kbar at temperatures of 60-300 K are presented as an example of the use of the magnetometer.
BibTeX: @article{Panfilov20151029, author = {Panfilov, A.S.}, title = {Use of a pendulum magnetometer for measuring the magnetic susceptibility of solids under pressure: The compound V₄S₉Br₄}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2015}, volume = {41}, number = {12}, pages = {1029-1033}, doi = {http://dx.doi.org/10.1063/1.4938094} }
Panfilov A., Grechnev G., Ishchuk V.	Effect of pressure on the magnetic properties of multiferroic BiFeO₃ [Abstract] [BibTeX]	2015	Low Temperature Physics Vol. 41(7), pp. 528-533	DOI
Abstract: Chemical bonds and their manifestations in the magnetism of ground-state multiferroic BiFeO₃ are studied theoretically. The magnetic properties of BiFeO₃ in the antiferromagnetic state and their dependences on hydrostatic pressure are studied experimentally and theoretically. These results indicate a substantial rise in the magnetic susceptibility χ of the compound under pressure with a characteristic pressure derivative dlnχ/dP ~ 3 × 10-2 GPa-1. A quantitative estimate of the magnetostriction is made on the basis of this value for the derivative and it is shown that a magnetostriction mechanism predominates in the interactions of the magnetic and electric subsystems of multiferroic BiFeO₃.
BibTeX: @article{Panfilov2015528, author = {Panfilov, A.S. and Grechnev, G.E. and Ishchuk, V.M.}, title = {Effect of pressure on the magnetic properties of multiferroic BiFeO₃}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2015}, volume = {41}, number = {7}, pages = {528-533}, doi = {http://dx.doi.org/10.1063/1.4927080} }
Panfilov A., Grechnev G., Fedorchenko A., Conder K., Pomjakushina E.	Magnetic properties of Mn-doped Bi2Se3 compound: Temperature dependence and pressure effects [Abstract] [BibTeX]	2015	Journal of Physics Condensed Matter Vol. 27(45), pp. 456002	DOI
Abstract: Magnetic susceptibility χ of Bi2-xMnxSe3 (x = 0.01-0.2) was measured in the temperature range 4.2-300 K. For all the samples, a Curie-Weiss behaviour of was revealed with effective magnetic moments of Mn ions corresponding to the spin value S = 5/2, which couple antiferromagnetically with the paramagnetic Curie temperature K. In addition, for the samples of nominal composition x = 0.1 and 0.2 the effect of a hydrostatic pressure P up to 2 kbar on χ has been measured at fixed temperatures 78 and 300 K that allowed to estimate the pressure derivative of to be K kbar-1. Based on the observed behaviour of with varied Mn concentration and pressure, a possible mechanism of interaction between localized Mn moments is discussed.
BibTeX: @article{Panfilov2015a, author = {Panfilov, A.S. and Grechnev, G.E. and Fedorchenko, A.V. and Conder, K. and Pomjakushina, E.V.}, title = {Magnetic properties of Mn-doped Bi2Se3 compound: Temperature dependence and pressure effects}, journal = {Journal of Physics Condensed Matter}, publisher = {Institute of Physics Publishing}, year = {2015}, volume = {27}, number = {45}, pages = {456002}, doi = {http://dx.doi.org/10.1088/0953-8984/27/45/456002} }
Grechnev G.E.	Igor Vadimovich Svechkarev (On his 80th birthday) [BibTeX]	2015	Low Temperature Physics Vol. 41(12), pp. 945	DOI
BibTeX: @article{grechnev2015, author = {Grechnev, G. E.}, title = {Igor Vadimovich Svechkarev (On his 80th birthday)}, journal = {Low Temperature Physics}, publisher = {AMER INST PHYSICS}, year = {2015}, volume = {41}, number = {12}, pages = {945}, doi = {http://dx.doi.org/10.1063/1.4937803} }
Dalakova N., Belevtsev B., Belyaev E., Panfilov A., Bobrysheva N., Selyutin A.	Low-temperature nonlinear effects in the conductivity of lightly doped cuprates La_2-xSr_xCuO₄ in antiferromagnetic state [Abstract] [BibTeX]	2014	Low Temperature Physics Vol. 40(5), pp. 397-407	DOI
Abstract: Low-temperature conductivity of antiferromagnetic cuprates La_2-xSr_xCuO₄ prepared by solid-phase synthesis was investigated. The concentration of strontium in the samples was 0.01, 0.005 and 0.001. In the temperature range T < 100K for all the samples the conduction mechanism corresponded to 3D variable-range hopping. For T > T_N (where T_N is the Neel temperature) a transition to the metallic type of conductivity was observed. Nonlinear effects in low-temperature conductivity, magnetoresistivity, as well as current-controlled negative differential resistance were found. It was established that the nonlinear behavior of conductivity intensified with decreasing the strontium concentration. For temperatures T < 10 K, the effect of positive magnetoresistance was observed. It is suggested that this effect can be attributed to the presence of a new low-- temperature magnetic phase (spin density waves).
BibTeX: @article{Dalakova2014397, author = {Dalakova, N.V. and Belevtsev, B.I. and Belyaev, E.Y. and Panfilov, A.S. and Bobrysheva, N.P. and Selyutin, A.A.}, title = {Low-temperature nonlinear effects in the conductivity of lightly doped cuprates La_2-xSr_xCuO₄ in antiferromagnetic state}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2014}, volume = {40}, number = {5}, pages = {397-407}, doi = {http://dx.doi.org/10.1063/1.4881175} }
Fertman E., Dolya S., Desnenko V., Pozhar L., Kajňaková M., Feher A.	Exchange bias in phase-segregated Nd2/3Ca1/3MnO 3 as a function of temperature and cooling magnetic fields [Abstract] [BibTeX]	2014	Journal of Applied Physics Vol. 115(20), pp. 203906	DOI
Abstract: Exchange bias (EB) phenomena have been observed in Nd2/3Ca 1/3MnO3 colossal magnetoresistance perovskite below the Curie temperature TC ∼ 70 K and attributed to an antiferromagnetic-ferromagnetic (FM) spontaneous phase segregated state of this compound. Field cooled magnetic hysteresis loops exhibit shifts toward negative direction of the magnetic field axis. The values of exchange field H EB and coercivity HC are found to be strongly dependent of temperature and strength of the cooling magnetic field Hcool. These effects are attributed to evolution of the FM phase content and a size of FM clusters. A contribution to the total magnetization of the system due to the FM phase has been evaluated. The exchange bias effect decreases with increasing temperature up to TC and vanishes above this temperature with disappearance of FM phase. Relaxation of a non-equilibrium magnetic state of the compound manifests itself through a training effect also observed while studying EB in Nd2/3Ca1/3MnO3.
BibTeX: @article{Fertman2014, author = {Fertman, E. and Dolya, S. and Desnenko, V. and Pozhar, L.A. and Kajňaková, M. and Feher, A.}, title = {Exchange bias in phase-segregated Nd2/3Ca1/3MnO 3 as a function of temperature and cooling magnetic fields}, journal = {Journal of Applied Physics}, publisher = {American Institute of Physics Inc.}, year = {2014}, volume = {115}, number = {20}, pages = {203906}, doi = {http://dx.doi.org/10.1063/1.4879416} }
Fertman E., Dolya S., Desnenko V., Kajňaková M., Feher A.	Exchange bias associated with phase separation in the Nd2/3Ca1/3MnO3 manganite [Abstract] [BibTeX]	2014	Low Temperature Physics Vol. 40(2), pp. 156-159	DOI
Abstract: The exchange bias (EB) phenomenon has been found in Nd2/3Ca1/3MnO3 perovskite. The phenomenon manifests itself as a negative horizontal shift of magnetization hysteresis loops. The EB phenomenon is evident of an interface exchange coupling between coexisting antiferromagnetic (AFM) and ferromagnetic (FM) phases and confirms the phase separated state of the compound at low temperatures. The EB effect is found to be strongly dependent on the cooling magnetic field and the temperature, which is associated with the evolution of spontaneous AFM-FM phase separated state of the compound. Analysis of magnetic hysteresis loops has shown that ferromagnetic moment MFM originating from the FM clusters saturates in a relatively low magnetic field about H ∼ 0.4 T. The obtained saturation value MFM (1 T) ~ 0.45 μB is in a good agreement with our previous neutron diffraction data.
BibTeX: @article{Fertman2014156, author = {Fertman, E. and Dolya, S. and Desnenko, V. and Kajňaková, M. and Feher, A.}, title = {Exchange bias associated with phase separation in the Nd2/3Ca1/3MnO3 manganite}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2014}, volume = {40}, number = {2}, pages = {156-159}, doi = {http://dx.doi.org/10.1063_1.4865563} }
Gaydamak T., Zvyagina G., Zhekov K., Bilich I., Desnenko V., Kharchenko N., Fil V.	Acoustopiezomagnetism and the elastic moduli of CoF₂ [Abstract] [BibTeX]	2014	Low Temperature Physics Vol. 40(6), pp. 524-530	DOI
Abstract: The piezomagnetic response of single crystal CoF₂ is studied using acoustic oscillations at frequencies of ~55 MHz. Without an external magnetic field the results reproduce the data from direct static measurements. A magnetic field opens up an additional piezomagnetic response channel with an amplitude that is linear in the field strength. The efficiencies of the two channels become equal in the antiferromagnetic state for H ~ 3 T. Above the Neel temperature the mechanism for the first channel ceases to operate, while the piezomagnetic response associated with the new channel falls off approximately exponentially. The sound speeds for the different crystallographic directions are measured and the components of the elastic modulus tensor are calculated.
BibTeX: @article{Gaydamak2014524, author = {Gaydamak, T.N. and Zvyagina, G.A. and Zhekov, K.R. and Bilich, I.V. and Desnenko, V.A. and Kharchenko, N.F. and Fil, V.D.}, title = {Acoustopiezomagnetism and the elastic moduli of CoF₂}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2014}, volume = {40}, number = {6}, pages = {524-530}, doi = {http://dx.doi.org/10.1063/1.4883897} }
Grechnev G., Panfilov A., Fedorchenko A., Lyogenkaya A., Zhuravleva I., Chareev D., Nekrasov A., Mitrofanova E., Volkova O., Vasiliev A., Eriksson O.	Anisotropy of magnetic properties of Fe1+yTe [Abstract] [BibTeX]	2014	Journal of Physics Condensed Matter Vol. 26(43), pp. 436003	DOI
Abstract: The magnetic properties of Fe1+yTe single crystals (y≃ 0.10.18) were studied at temperatures 4.2300K. At an ambient pressure, with decreasing temperature a drastic drop in χ(T) was confirmed at T≃ 6065K, which appears to be closely related to the antiferromagnetic (AFM) ordering. It is found that the magnitudes of the anisotropy of magnetic susceptibility Δχ in the AFM phase are close in the studied samples, whereas the sign of the anisotropy apparently depends on the small variations of the excess iron y in Fe1+yTe samples. The performed DFT calculations of the electronic structure and magnetic properties for the stoichiometric FeTe compound indicate the presence of frustrated AFM ground states. There are very close energies and magnetic moments for the double stripe configurations, with the AFM axes oriented either on the basal plane or along the [0 0 1] direction. Presumably, both these configurations can be realized in Fe1+yTe single crystals, depending on the variations of the excess iron. This can provide different signs of magnetic anisotropy in the AFM phase, presently observed in the Fe1+yTe samples. For these types of AFM configuration, the calculations for the FeTe values of Δχ are consistent with our experimental data.
BibTeX: @article{Grechnev2014, author = {Grechnev, G.E. and Panfilov, A.S. and Fedorchenko, A.V. and Lyogenkaya, A.A. and Zhuravleva, I.P. and Chareev, D.A. and Nekrasov, A.N. and Mitrofanova, E.S. and Volkova, O.S. and Vasiliev, A.N. and Eriksson, O.}, title = {Anisotropy of magnetic properties of Fe1+yTe}, journal = {Journal of Physics Condensed Matter}, publisher = {Institute of Physics Publishing}, year = {2014}, volume = {26}, number = {43}, pages = {436003}, doi = {http://dx.doi.org/10.1088/0953-8984/26/43/436003} }
Grechnev G., Logosha A., Lyogenkaya A., Grechnev A., Fedorchenko A.	Electronic structure and properties of novel layered superconductors [Abstract] [BibTeX]	2014	Ukrainian Journal of Physics Vol. 59(3), pp. 284-291	DOI
Abstract: The electronic energy structures and magnetic properties of layered superconductors RNi2B2C, RFe4Al8, and FeSe are systematically studied, by using the density functional theory (DFT). The calculations allowed us to reveal a number of features of the electronic structure, which can cause the manifestation of peculiar structural, magnetic and superconducting properties of these systems. It is demonstrated that the Fermi energy EF is located close to the pronounced peaks of the electronic density of states (DOS). The main contribution to DOS at the Fermi level arises from 3d-electrons. The calculations of the pressure-dependent electronic structure and the magnetic susceptibility in the normal state indicate that the novel superconductors are very close to a magnetic instability with dominating spin paramagnetism. It is shown that experimental data on the pressure dependence of the superconducting transition temperature in FeSe correlate qualitatively with the calculated behavior of DOS at EF as a function of the pressure.
BibTeX: @article{Grechnev2014284, author = {Grechnev, G.E. and Logosha, A.V. and Lyogenkaya, A.A. and Grechnev, A.G. and Fedorchenko, A.V.}, title = {Electronic structure and properties of novel layered superconductors}, journal = {Ukrainian Journal of Physics}, publisher = {National Academy of Sciences of Ukraine}, year = {2014}, volume = {59}, number = {3}, pages = {284-291}, doi = {http://dx.doi.org/10.15407/ujpe59.03.0284} }
Grechnev G., Lyogenkaya A., Pluzhnikov V., Svechkarev I., Fedorchenko A., Perz J.	De Haas-van Alphen effect in the band antiferromagnet FeGe₂: Development of spin splitting [Abstract] [BibTeX]	2014	Low Temperature Physics Vol. 40(4), pp. 384-387	DOI
Abstract: The de Haas-van Alphen (dHvA) effect in the antiferromagnetic compound FeGe₂ is studied experimentally. A sharp suppression of the amplitude of the first harmonic of the dHvA oscillations is observed for a number of orbits on the Fermi surface of FeGe₂. The change in the conditions for suppression of the amplitude ("spin zeroes") when FeGe₂ is doped with cobalt is determined. A method for analyzing the experimental data is proposed in which the g-factors of the conduction electrons are computed on the basis of calculations of the spin-polarized electron structure of the band antiferromagnet taking spin-orbital interactions into account. The exchange enhancement factor for spin paramagnetism in FeGe₂ is also calculated.
BibTeX: @article{Grechnev2014384, author = {Grechnev, G.E. and Lyogenkaya, A.A. and Pluzhnikov, V.B. and Svechkarev, I.V. and Fedorchenko, A.V. and Perz, J.M.}, title = {De Haas-van Alphen effect in the band antiferromagnet FeGe₂: Development of spin splitting}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2014}, volume = {40}, number = {4}, pages = {384-387}, doi = {http://dx.doi.org/10.1063/1.4871750} }
Grechnev G., Lyogenkaya A., Kolesnichenko Y., Prylutskyy Y., Hayn R.	Electronic structure and magnetic properties of graphite intercalated with 3d-metals [Abstract] [BibTeX]	2014	Low Temperature Physics Vol. 40(5), pp. 450-453	DOI
Abstract: Electronic structure and magnetic properties of graphite-based systems with intercalated 3d-transition metal atoms (V, Cr, Mn, Fe, Co, Ni) were calculated ab initio using the density functional theory. The presence of different magnetic states depending on the type of inserted M atoms is revealed for hexagonal P6/mmm and P6₃/mmc crystall structures. The values of magnetic moments appeared to be governed by the p-d hybridization, and by variations of exchange interactions with intercalation. The results of calculations clearly indicate itinerancy of the 3d-electrons of inserted M atoms.
BibTeX: @article{Grechnev2014450, author = {Grechnev, G.E. and Lyogenkaya, A.A. and Kolesnichenko, Y.A. and Prylutskyy, Y.I. and Hayn, R.}, title = {Electronic structure and magnetic properties of graphite intercalated with 3d-metals}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2014}, volume = {40}, number = {5}, pages = {450-453}, doi = {http://dx.doi.org/10.1063/1.4876224} }
Logosha A., Grechnev G., Lyogenkaya A., Panfilov A.	Features of the electronic structure of the layered superconductors RNi₂B₂C, RFe₄Al₈, and FeSe [Abstract] [BibTeX]	2014	Low Temperature Physics Vol. 40(4), pp. 311-317	DOI
Abstract: The electronic structure and a number of thermodynamic characteristics of layered magnetic superconductors in the systems RNi₂B₂C, RFe₄Al₈, and FeSe in the normal state are calculated from first principles. The electronic states and the interactions responsible for the electronic, structural, and magnetic properties of these systems are analyzed.
BibTeX: @article{Logosha2014311, author = {Logosha, A.V. and Grechnev, G.E. and Lyogenkaya, A.A. and Panfilov, A.S.}, title = {Features of the electronic structure of the layered superconductors RNi₂B₂C, RFe₄Al₈, and FeSe}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2014}, volume = {40}, number = {4}, pages = {311-317}, doi = {http://dx.doi.org/10.1063/1.4871747} }
Panfilov A., Grechnev G., Filipov V., Lyashchenko A., Levchenko G.	Magnetic properties of MeB50 (Me = 3d Atom) compounds [Abstract] [BibTeX]	2014	Acta Physica Polonica A Vol. 126(1), pp. 400-401	DOI
Abstract: Temperature dependence of the static magnetic susceptibility for higher borides MeB50, where Me = V, Cr, Mn, Fe, Co and Ni, was measured by Faraday method in the temperature range of 78-300 K. The value of effective magnetic moment of 3d-ions, resulted from the experiment, is compared with corresponding data of the ab initio calculations of the electronic structure and magnetic properties of these compounds based on the density functional theory.
BibTeX: @article{Panfilov2014400, author = {Panfilov, A.S. and Grechnev, G.E. and Filipov, V.B. and Lyashchenko, A.B. and Levchenko, G.V.}, title = {Magnetic properties of MeB50 (Me = 3d Atom) compounds}, journal = {Acta Physica Polonica A}, publisher = {Polish Academy of Sciences}, year = {2014}, volume = {126}, number = {1}, pages = {400-401}, doi = {http://dx.doi.org/10.12693/APhysPolA.126.400} }
Panfilov A., Pashchenko V., Grechnev G., Desnenko V., Fedorchenko A., Bludov A., Gnatchenko S., Chareev D., Mitrofanova E., Vasiliev A.	Interrelation of superconductivity and magnetism in FeSe_1-xTe_x compounds. Pressure effects [Abstract] [BibTeX]	2014	Low Temperature Physics Vol. 40(7), pp. 615-620	DOI
Abstract: The effect of isotropic pressures P up to 5 kbar on the superconducting transition temperature T_c of the FeSe_1-xTe_x system (x=0, 0.85, 0.88, 0.90) is studied. For the first time, a change in the sign of the effect of pressure on T_c on going from FeSe to the tellurium-rich alloys is observed. This makes it possible to specify more precisely the form of the dependence of the pressure derivative dT_c/dP on composition in this system. This dependence is compared with first principles calculations of the electron structure and magnetism of FeSe, FeTe, and FeSe_0.5Te_0.5 as functions of pressure, as well as with our earlier experimental data on the effect of pressure on the magnetic susceptibility of the normal state in FeSe and FeTe. This comparison is indicative of a competitive interrelationship between superconductivity and magnetism in tellurium rich FeSe_1-xTe_x compounds.
BibTeX: @article{Panfilov2014615, author = {Panfilov, A.S. and Pashchenko, V.A. and Grechnev, G.E. and Desnenko, V.A. and Fedorchenko, A.V. and Bludov, A.N. and Gnatchenko, S.L. and Chareev, D.A. and Mitrofanova, E.S. and Vasiliev, A.N.}, title = {Interrelation of superconductivity and magnetism in FeSe_1-xTe_x compounds. Pressure effects}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2014}, volume = {40}, number = {7}, pages = {615-620}, doi = {http://dx.doi.org/10.1063/1.4890990} }
Sirenko V., Eremenko V.	The universality of the magnetization irreversibility line of metglasses and superconductors [Abstract] [BibTeX]	2014	Low Temperature Physics Vol. 40(9), pp. 859	DOI
Abstract: An analysis of the experimental data of the temperature dependence of metallic glass and superconductor magnetization. A common feature is the irreversibility of magnetization: below a certain temperature T, under fixed field strength, magnetization varies during cooling within (MFC), and outside (MZFC) of a magnetic field. It is demonstrated that for all samples, the line T(H) is universal, and corresponds to the theoretical dependence of de Almeida-Thouless (T* ~ H2/3) in all studied ranges of magnetic fields.
BibTeX: @article{Sirenko2014, author = {Sirenko, V.A. and Eremenko, V.V.}, title = {The universality of the magnetization irreversibility line of metglasses and superconductors}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2014}, volume = {40}, number = {9}, pages = {859}, doi = {http://dx.doi.org/10.1063/1.4897012} }
Sirenko V., Eremenko V.	Irreversibility and anisotropy of the low-temperature magnetization in manganites. Spin-glass polyamorphism [Abstract] [BibTeX]	2014	Low Temperature Physics Vol. 40(2), pp. 179-184	DOI
Abstract: The temperature dependences of the magnetization in manganites of different composition and structural morphology were measured in two cooling regimes, field cooling (FC) and zero-field cooling (ZFC), for two different orientations of a magnetic field, parallel and perpendicular to the c-axis. The following general tendencies were found: (1) The difference between the magnetizations MFC and MZFC at T = 5K increases with increasing magnetic field, reaching the maximum value in a magnetic field of about 2 kOe, and then drops in the range 2-5 kOe; (2) The field dependence of the "splitting" temperature T* below which the difference between the magnetizations MFC and MZFC appears can be reasonably well described by a power law with the exponent 2/3 as predicted by the theory of spin glasses. Both results are characteristic for single crystals, as well as for ceramics and films. On the other hand, the field dependence of the anisotropy of magnetic susceptibility is different for samples with different degrees of magnetic ordering (Θ/TC). These results are consistent with the detected in the present study universality of the line separating the low-temperature region of irreversibility in the H-T phase diagram of manganites. Deviations from the T* H-line with the exponent 2/3 in strong magnetic fields, which are commonly associated with the appearance of the magnetization component transverse to the magnetic field, are typical for samples containing the antiferromagnetic phase. The interpretation takes into account the multi-phase nature of the systems, i.e., coexistence of spin glass with ferromagnetism and antiferromagnetism. The observed change in the anisotropy of magnetic susceptibility with increasing magnetic field and the behavior of magnetic and thermomagnetic irreversibility are regarded as a manifestation of the spin-reorientation phase transition in an antiferromagnetic environment. This in turn initiates the transformation of the spin-glass-from the Ising- to the Heisenberg-type-which leads to the change in the exponent in the T*H diagram from 2/3 to 2. The observed phenomenon is universal-it was observed in manganites of different composition and structural morphology-and represents a particular type of polyamorphism, namely, spin-glass polyamorphism.
BibTeX: @article{Sirenko2014179, author = {Sirenko, V.A. and Eremenko, V.V.}, title = {Irreversibility and anisotropy of the low-temperature magnetization in manganites. Spin-glass polyamorphism}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2014}, volume = {40}, number = {2}, pages = {179-184}, doi = {http://dx.doi.org/10.1063_1.4865567} }
Sirenko V., Eremenko V.	Universality of the magnetization irreversibility curve of systems with competing interactions (manganites, cobaltites, ferrites) [Abstract] [BibTeX]	2014	Low Temperature Physics Vol. 40(6), pp. 521-523	DOI
Abstract: Experimental data on the temperature dependences of the magnetization of manganites, cobaltites, and ferrites are analyzed. Their common feature is magnetization irreversibility: below a temperature T* for a fixed field strength, the magnetization is different for cooling in a field (M_FC) and in zero field (M_ZFC). It is shown that the T(H) curve is universal for all the dispersed oxides (nanocompound, nanopowder) and is consistent with the theoretical Almeida-Thouless curve (T~H2/3) over the entire range of magnetic fields. In the case of monolithic samples (single crystals, ceramics), in strong magnetic fields there is a transition to a quadratic dependence T* ~ H2 in agreement with the Gabay-Toulousse theory. This phenomenon is interpreted in terms of spin-glass polyamorphism.
BibTeX: @article{Sirenko2014521, author = {Sirenko, V.A. and Eremenko, V.V.}, title = {Universality of the magnetization irreversibility curve of systems with competing interactions (manganites, cobaltites, ferrites)}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2014}, volume = {40}, number = {6}, pages = {521-523}, doi = {http://dx.doi.org/10.1063/1.4883896} }
Zvyagina G., Zhekov K., Bilych I., Zvyagin A., Bludov A., Pashchenko V., Gudim I.	Magnetic field-induced phase transitions in the antiferromagnet Nd_0.6Dy_0.4Fe₃(BO₃)₄ [Abstract] [BibTeX]	2014	Low Temperature Physics Vol. 40(2), pp. 146-150	DOI
Abstract: Low-temperature studies of elastic and magnetic characteristics of the single crystal Nd_0.6Dy_0.4Fe₃(BO₃)₄ have been performed. A transition to the antiferromagnetically ordered state of the magnetic subsystem has been manifested in the temperature behavior of the velocity and attenuation of acoustic modes and magnetization. Spin-reorientation phase transitions, which reveal themselves as anomalies in the behavior of elastic and magnetic characteristics of the crystal in the external magnetic field applied along the axis of the trigonal symmetry of the crystal have been discovered. The phase H-T diagram for Hk C₃ has been constructed.
BibTeX: @article{Zvyagina2014146, author = {Zvyagina, G.A. and Zhekov, K.R. and Bilych, I.V. and Zvyagin, A.A. and Bludov, A.N. and Pashchenko, V.A. and Gudim, I.A.}, title = {Magnetic field-induced phase transitions in the antiferromagnet Nd_0.6Dy_0.4Fe₃(BO₃)₄}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2014}, volume = {40}, number = {2}, pages = {146-150}, doi = {http://dx.doi.org/10.1063/1.4865561} }
Zvyagina G.	Magnetoelastic properties of Nd_0.9Dy_0.1Fe₃(BO₃)₄ ferroborate [Abstract] [BibTeX]	2014	Low Temperature Physics Vol. 40(5), pp. 454-457	DOI
Abstract: The low-temperature elastic characteristics of single-crystal Nd_0.9Dy_0.1Fe₃(BO₃)₄ are studied. A transition of the magnetic system into an antiferromagnetic ordered state and a spontaneous spin-reorientation phase transition are observed in the temperature behavior of the speed and absorption of acoustic modes. Two anomalies in the speed and absorption of transverse acoustic modes are discovered at the lowest experimental temperature of 1.7K in an external magnetic field directed along the trigonal axis of the crystal. These features are associated with two reorientation phase transitions that follow one another.
BibTeX: @article{Zvyagina2014454, author = {Zvyagina, G.A.}, title = {Magnetoelastic properties of Nd_0.9Dy_0.1Fe₃(BO₃)₄ ferroborate}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2014}, volume = {40}, number = {5}, pages = {454-457}, doi = {http://dx.doi.org/10.1063/1.4878123} }
Fil V., Fil D., Zhekov K., Gaydamak T., Zvyagina G., Bilich I., Chareev D., Vasiliev A.	Piezomagnetism of FeSe single crystals [Abstract] [BibTeX]	2013	EPL Vol. 103(4), pp. 47009	DOI
Abstract: The acoustic-electric transformation in high-quality FeSe single crystals is studied. In zero magnetic field we observe an abnormally strong electromagnetic radiation induced by a transverse elastic wave. Usually a radiation of such intensity and polarization is observed only in metals subjected to a high magnetic field (the radiation is caused by the Hall current). We argue that in FeSe in zero magnetic field it is caused by the piezomagnetic effect which is most probably of dynamical origin. We find that the piezomagnetism survives under the transition from the normal to superconducting state. In the superconducting state the electromagnetic signal decreases with decreasing temperature that is connected with the change in the London penetration depth.
BibTeX: @article{Fil2013, author = {Fil, V.D. and Fil, D.V. and Zhekov, K.R. and Gaydamak, T.N. and Zvyagina, G.A. and Bilich, I.V. and Chareev, D.A. and Vasiliev, A.N.}, title = {Piezomagnetism of FeSe single crystals}, journal = {EPL}, year = {2013}, volume = {103}, number = {4}, pages = {47009}, doi = {http://dx.doi.org/10.1209/0295-5075/103/47009} }
Gospodarev I., Eremenko A., Kravchenko K., Sirenko A., Sirenko V., Syrkin E., Feodosyev S., Shabakaeva Y.	Distinctive features of thermal expansion of niobium diselenide [Abstract] [BibTeX]	2013	Physics of the Solid State Vol. 55(4), pp. 898-904	DOI
Abstract: The characteristic features of thermal expansion of bulk samples of niobium diselenide have been determined experimentally and analyzed theoretically. The manifestation of the so-called membrane effect in this compound due to the significant difference in the temperature dependences of the mean-square amplitudes of atomic displacements in the parallel and perpendicular directions toward the layers has been investigated.
BibTeX: @article{Gospodarev2013898, author = {Gospodarev, I.A. and Eremenko, A.V. and Kravchenko, K.V. and Sirenko, A.F. and Sirenko, V.A. and Syrkin, E.S. and Feodosyev, S.B. and Shabakaeva, Y.A.}, title = {Distinctive features of thermal expansion of niobium diselenide}, journal = {Physics of the Solid State}, year = {2013}, volume = {55}, number = {4}, pages = {898-904}, doi = {http://dx.doi.org/10.1134/S1063783413040112} }
Grechnev G., Panfilov A., Desnenko V., Fedorchenko A., Gnatchenko S., Chareev D., Volkova O., Vasiliev A.	Magnetic properties of superconducting FeSe in the normal state [Abstract] [BibTeX]	2013	Journal of Physics Condensed Matter Vol. 25(4), pp. 046004	DOI
Abstract: A detailed magnetization study for the novel FeSe superconductor is carried out to investigate the behavior of the intrinsic magnetic susceptibility χ in the normal state with temperature and under hydrostatic pressure. The temperature dependences of χ and its anisotropy Δχ = χ- χ are measured for FeSe single crystals in the temperature range 4.2-300 K, and a substantial growth of susceptibility with temperature is revealed. The observed anisotropy Δχ is very large and comparable to the averaged susceptibility at low temperatures. For a polycrystalline sample of FeSe, the significant pressure effect on χ is determined to be essentially dependent on temperature. Ab initio calculations of the pressure-dependent electronic structure and magnetic susceptibility indicate that FeSe is close to magnetic instability, with dominating enhanced spin paramagnetism. The calculated paramagnetic susceptibility exhibits a strong dependence on the unit cell volume and especially on the height Z of chalcogen species from the Fe plane. The change of Z under pressure determines a large positive pressure effect on χ, which is observed at low temperatures. It is shown that the literature experimental data on the strong and nonmonotonic pressure dependence of the superconducting transition temperature in FeSe correlate qualitatively with the calculated behavior of the density of electronic states at the Fermi level.
BibTeX: @article{Grechnev2013, author = {Grechnev, G.E. and Panfilov, A.S. and Desnenko, V.A. and Fedorchenko, A.V. and Gnatchenko, S.L. and Chareev, D.A. and Volkova, O.S. and Vasiliev, A.N.}, title = {Magnetic properties of superconducting FeSe in the normal state}, journal = {Journal of Physics Condensed Matter}, year = {2013}, volume = {25}, number = {4}, pages = {046004}, doi = {http://dx.doi.org/10.1088/0953-8984/25/4/046004} }
Grechnev G., Desnenko V., Fedorchenko A., Panfilov A., Kolesnichenko Y., Khrapatiy S., Prylutskyy Y., Matzui L., Ritter U., Scharff P.	Magnetic properties of N-doped multi-walled carbon nanotubes [Abstract] [BibTeX]	2013	Materialwissenschaft und Werkstofftechnik Vol. 44(2-3), pp. 136-138	DOI
Abstract: The magnetic properties of nitrogen-doped multi-walled carbon nanotubes (N-MWCNTs) were studied in the temperature and magnetic field range of (4.2-290) K and (0.05-30) kOe, respectively. Also magnetic properties of the reference MWCNTs without nitrogen doping were investigated on the same footing for comparison. The presence of iron-based particles inside N-MWCNTs was detected. The low temperature SQUID (Superconducting Quantum Interference Device) magnetization measurements were supplemented with thermogravimetric analysis. The magnetic characterization provided the saturation magnetic moment M S and residual magnetization MR of N-MWCNTs to be, respectively, 4.5 emu/g and 0.9 emu/g, whereas for the reference MWCNTs the corresponding parameters are found to be about twice higher. The coercive field value amounts to 800 Oe for both systems at low temperatures, then decreasing to about 450 Oe at 200 K.
BibTeX: @article{Grechnev2013136, author = {Grechnev, G.E. and Desnenko, V.A. and Fedorchenko, A.V. and Panfilov, A.S. and Kolesnichenko, Y.A. and Khrapatiy, S.V. and Prylutskyy, Y.I. and Matzui, L.Y. and Ritter, U. and Scharff, P.}, title = {Magnetic properties of N-doped multi-walled carbon nanotubes}, journal = {Materialwissenschaft und Werkstofftechnik}, year = {2013}, volume = {44}, number = {2-3}, pages = {136-138}, doi = {http://dx.doi.org/10.1002/mawe.201300083} }
Sirenko V., Rykova A., Eremenko A.	Magnetic state of the manganite nanocompound La0.8Mn1.04O3.5 [Abstract] [BibTeX]	2013	Low Temperature Physics Vol. 39(8), pp. 719-721	DOI
Abstract: Published data on the temperature dependences M(T) of the magnetization of different manganites and the compound La0.8Mn1.04O3.5 are compared. The results of measurements with cooling in a magnetic field and for zero field are the same only above the splitting temperature T. This temperature depends on the magnetic field strength at which the M(T) curves are measured. The relative change in T, which is described by a power-law function with an exponent less than 1, as is typical of spin glass, is compared for all the ceramic samples. La0.8Mn1.04O3.5, which consists of particles with sizes of about 70 nm, is an exception. The behavior of [T(H)-T(0)]/T*(H) for this manganite is similar to that for a supermagnet with weak interactions.
BibTeX: @article{Sirenko2013719, author = {Sirenko, V.A. and Rykova, A.I. and Eremenko, A.V.}, title = {Magnetic state of the manganite nanocompound La0.8Mn1.04O3.5}, journal = {Low Temperature Physics}, year = {2013}, volume = {39}, number = {8}, pages = {719-721}, doi = {http://dx.doi.org/10.1063/1.4818635} }
Troyanchuk I., Bushinsky M., Nikitin A., Lobanovsky L., Dobriansky V., Eremenko V., Sirenko V.	The condition for a large magnetoresistance effect in perovskite cobaltites [Abstract] [BibTeX]	2013	Low Temperature Physics Vol. 39(11), pp. 948	DOI
Abstract: The magnetic and magnetotransport properties of the anion-deficient perovskites La1-xBaxCoO3-δ are studied. It is shown that a gradual transition from the metallic to the semiconductor conduction and from ferromagnetism to antiferromagnetism takes place when the oxygen content decreases. The magnetoresistance is maximal at low temperatures near the concentration limit of the magnetic phase transition. A large value of the magnetoresistance is explained by the magnetic-field induced transition to a more conductive ferromagnetic phase, which occurs simultaneously with the change of a spin state of cobalt ions.
BibTeX: @article{Troyanchuk2013, author = {Troyanchuk, I.O. and Bushinsky, M.V. and Nikitin, A.V. and Lobanovsky, L.S. and Dobriansky, V.M. and Eremenko, V.V. and Sirenko, V.A.}, title = {The condition for a large magnetoresistance effect in perovskite cobaltites}, journal = {Low Temperature Physics}, year = {2013}, volume = {39}, number = {11}, pages = {948}, doi = {http://dx.doi.org/10.1063/1.4830262} }
Zvyagina G., Gaydamak T., Zhekov K., Bilich I., Fil V., Chareev D., Vasiliev A.	Acoustic characteristics of FeSe single crystals [Abstract] [BibTeX]	2013	EPL Vol. 101(5), pp. 56005	DOI
Abstract: The results of the comprehensive ultrasonic research of high-quality single crystals of FeSe are presented. Absolute values of sound velocities and their temperature dependences were measured; elastic constants and Debye temperature were calculated. The elastic C11-C12 and C11 constants undergo significant softening under the structural tetra-ortho transformation. The significant influence of the superconducting transition on the velocity and attenuation of sound was revealed and the value of the superconducting energy gap was estimated.
BibTeX: @article{Zvyagina2013, author = {Zvyagina, G.A. and Gaydamak, T.N. and Zhekov, K.R. and Bilich, I.V. and Fil, V.D. and Chareev, D.A. and Vasiliev, A.N.}, title = {Acoustic characteristics of FeSe single crystals}, journal = {EPL}, year = {2013}, volume = {101}, number = {5}, pages = {56005}, doi = {http://dx.doi.org/10.1209/0295-5075/101/56005} }
Zvyagina G., Zhekov K., Bilych I., Zvyagin A., Gudim I., Temerov V., Eremin E.	Magnetoelastic studies of Nd0.75Dy0.25Fe3(BO3)4 in the external magnetic field: Magnetic phase transitions [Abstract] [BibTeX]	2013	Low Temperature Physics Vol. 39(11), pp. 936	DOI
Abstract: We report on results of sound-velocity and sound-attenuation measurements in the Nd0.75Dy0.25Fe3(BO3)4 in external magnetic fields up to 5 T, applied along several directions with respect to crystallographic axes, and at temperatures down to 1.7 K. The experimental data are analyzed with a microscopic theory based on exchange-striction coupling and phenomenological theory resulting in a qualitative agreement between theoretical results and experimental data.
BibTeX: @article{Zvyagina2013a, author = {Zvyagina, G.A. and Zhekov, K.R. and Bilych, I.V. and Zvyagin, A.A. and Gudim, I.A. and Temerov, V.L. and Eremin, E.V.}, title = {Magnetoelastic studies of Nd0.75Dy0.25Fe3(BO3)4 in the external magnetic field: Magnetic phase transitions}, journal = {Low Temperature Physics}, year = {2013}, volume = {39}, number = {11}, pages = {936}, doi = {http://dx.doi.org/10.1063/1.4826082} }
Avramenko Y., Burma N., Petrishin A., Fil V.	Beam waves in tungsten [Abstract] [BibTeX]	2012	Low Temperature Physics Vol. 38(5), pp. 442-445	DOI
Abstract: The electromagnetic transparency of samples of single-crystal, high purity tungsten is studied at liquid helium temperatures in zero magnetic field. The velocity, damping, moduli, and initial phases of the excitation coefficients are measured for electromagnetic signals consisting of long wavelength beam waves and quasiwaves passing through the test samples. An anomaly is observed in the excitation of charge-carrier beam waves in flat segments of the Fermi surface.
BibTeX: @article{Avramenko2012442, author = {Avramenko, Y.A. and Burma, N.G. and Petrishin, A.I. and Fil, V.D.}, title = {Beam waves in tungsten}, journal = {Low Temperature Physics}, year = {2012}, volume = {38}, number = {5}, pages = {442-445}, doi = {http://dx.doi.org/10.1063/1.4707169} }
Burma N., Avramenko Y., Petrishin A., Fil V.	Effect of resonance electron-phonon interactions on the electronic spectra of tungsten and gallium [Abstract] [BibTeX]	2012	Low Temperature Physics Vol. 38(5), pp. 437-441	DOI
Abstract: Features of the angular dependences of the Fermi velocity of charge carriers in tungsten and gallium associated with resonance electron-phonon interactions are studied. These features show up as a substantial reduction, by at least a factor of 1.5, in the velocity in the direction of the normals to the flattened parts of the Fermi surfaces of these metals and as a much smaller, on the order of 5%, reduction in the velocity on a cylindrical Fermi surface.
BibTeX: @article{Burma2012437, author = {Burma, N.G. and Avramenko, Y.A. and Petrishin, A.I. and Fil, V.D.}, title = {Effect of resonance electron-phonon interactions on the electronic spectra of tungsten and gallium}, journal = {Low Temperature Physics}, year = {2012}, volume = {38}, number = {5}, pages = {437-441}, doi = {http://dx.doi.org/10.1063/1.4707168} }
Dalakova N., Belevtsev B., Bobrysheva N., Panfilov A., Beliayev E., Selyutin A.	Resistive properties of La 2- xSr xCuO 4 low-dopped cuprates in the antiferromagnetic state at low temperatures [Abstract] [BibTeX]	2012	Bulletin of the Russian Academy of Sciences: Physics Vol. 76(10), pp. 1139-1142	DOI
Abstract: The nonlinear dependence of conductivity and negative differential resistance of ceramic samples of La 2 - xSr xCuO 4 in the antiferromagnetic state is revealed. The possible influence of a spatially inhomoge- neous distribution of strontium impurities on the low-temperature behavior of conductivity is discussed.
BibTeX: @article{Dalakova20121139, author = {Dalakova, N.V. and Belevtsev, B.I. and Bobrysheva, N.P. and Panfilov, A.S. and Beliayev, E.Yu. and Selyutin, A.A.}, title = {Resistive properties of La 2- xSr xCuO 4 low-dopped cuprates in the antiferromagnetic state at low temperatures}, journal = {Bulletin of the Russian Academy of Sciences: Physics}, year = {2012}, volume = {76}, number = {10}, pages = {1139-1142}, doi = {http://dx.doi.org/10.3103/S1062873812100036} }
Desnenko V., Rykova A., Sirenko V., Fedorchenko A., Cherny A., Khatsko E., Eremenko A.	Magnetic phase segregation and glass nature of Pr 0.4Bi 0.3Ca 0.3MnO 3 manganite [Abstract] [BibTeX]	2012	Low Temperature Physics Vol. 38(3), pp. 206-209	DOI
Abstract: The results of detailed investigations of magnetic properties of Pr 0.4Bi 0.3Ca 0.3MnO 3 manganites at low temperatures are presented. The performed investigations of temperature, field and frequency dependences of magnetization and susceptibility as well as the magnetization relaxation processes indicate that below T C = 44 K the manganite Pr 0.4Bi 0.3Ca 0.3MnO 3 is in the magnetic phase-segregated state with ferromagnetic inclusions forming a cluster glass.
BibTeX: @article{Desnenko2012206, author = {Desnenko, V.A. and Rykova, A.I. and Sirenko, V.A. and Fedorchenko, A.V. and Cherny, A.S. and Khatsko, E.N. and Eremenko, A.V.}, title = {Magnetic phase segregation and glass nature of Pr 0.4Bi 0.3Ca 0.3MnO 3 manganite}, journal = {Low Temperature Physics}, year = {2012}, volume = {38}, number = {3}, pages = {206-209}, doi = {http://dx.doi.org/10.1063/1.3693578} }
Feher A., Desnenko V., Fertman E., Dolya S., Kajňaková M., Beznosov A.	Direct evidence of the low-temperature cluster-glass magnetic state of Nd2/3Ca1/3MnO3 perovskite [Abstract] [BibTeX]	2012	Low Temperature Physics Vol. 38(7), pp. 657-661	DOI
Abstract: A giant exchange bias is detected in the colossal magnetoresistance of Nd2/3Ca1/3MnO3 perovskite at low temperatures and is evidence of intrinsic exchange coupling in this compound. These phenomena confirm our previous assumption that the low-temperature magnetic structure of this compound consists of small (nanosized) ferromagnetic clusters embedded in a charge-ordered antiferromagnetic matrix. The magnetic behavior of the perovskite Nd2/3Ca1/3MnO3 is consistent with a cluster-glass magnetic state and inconsistent with the classical spin-glass state observed in a variety of disordered magnetic systems. We think that the cluster-glass magnetic behavior of Nd2/3Ca1/3MnO3 originates in a self-organized phase-separated state of the compound. A Cole-Cole analysis of the dynamic susceptibility at low temperatures reveals an extremely broad distribution of relaxation times, indicating that spins are frozen on a "macroscopic" time scale. Slow relaxation of the zero-field-cooled magnetization is also observed experimentally. This slow relaxation confirms the cluster-glass magnetic state of the compound. Two highly different relaxation mechanisms have been found: the first is characteristic of temperatures below the freezing temperature Tg ~ 60 K and the second, of higher temperatures.
BibTeX: @article{Feher2012657, author = {Feher, A. and Desnenko, V. and Fertman, E. and Dolya, S. and Kajňaková, M. and Beznosov, A.}, title = {Direct evidence of the low-temperature cluster-glass magnetic state of Nd2/3Ca1/3MnO3 perovskite}, journal = {Low Temperature Physics}, year = {2012}, volume = {38}, number = {7}, pages = {657-661}, doi = {http://dx.doi.org/10.1063/1.4736614} }
Fertman E., Dolya S., Desnenko V., Beznosov A., Kajňaková M., Feher A.	Cluster glass magnetism in the phase-separated Nd 2/3Ca 1/3MnO 3 perovskite [Abstract] [BibTeX]	2012	Journal of Magnetism and Magnetic Materials Vol. 324(19), pp. 3213-3217	DOI
Abstract: A detailed study of the low-temperature magnetic state and the relaxation in the phase-separated colossal magnetoresistance Nd 2/3Ca 1/3MnO 3 perovskite has been carried out. Clear experimental evidence of the cluster-glass magnetic behavior of this compound has been revealed. Well defined maxima in the in-phase linear ac susceptibility χ′(T) were observed, indicative of the magnetic glass transition at T g∼60 K. Strongly divergent zero-field-cooled and field-cooled static magnetizations and frequency dependent ac susceptibility are evident of the glassy-like magnetic state of the compound at low temperatures. The frequency dependence of the cusp temperature T max of the χ′(T) susceptibility was found to follow the critical slowing down mechanism. The Cole-Cole analysis of the dynamic susceptibility at low temperature has shown extremely broad distribution of relaxation times, indicating that spins are frozen at macroscopic time scale. Slow relaxation in the zero-field-cooled magnetization has been experimentally revealed. The obtained results do not agree with a canonical spin-glass state and indicate a cluster glass magnetic state of the compound below T g, associated with its antiferromagnetic-ferromagnetic nano-phase segregated state. It was found that the relaxation mechanisms below the cluster glass freezing temperature T g and above it are strongly different. Magnetic field up to about μ 0H∼0.4 T suppresses the glassy magnetic state of the compound.
BibTeX: @article{Fertman20123213, author = {Fertman, E. and Dolya, S. and Desnenko, V. and Beznosov, A. and Kajňaková, M. and Feher, A.}, title = {Cluster glass magnetism in the phase-separated Nd 2/3Ca 1/3MnO 3 perovskite}, journal = {Journal of Magnetism and Magnetic Materials}, year = {2012}, volume = {324}, number = {19}, pages = {3213-3217}, doi = {http://dx.doi.org/10.1016/j.jmmm.2012.05.043} }
Fertman E., Desnenko V., Dolya S., Kajnakova M., Feher A.	Giant exchange bias in nano phase-segregated Nd2/3Ca 1/3MnO3 [Abstract] [BibTeX]	2012	International Conference on Oxide Materials for Electronic Engineering, OMEE 2012, pp. 97-98	DOI
Abstract: We have revealed a giant exchange bias (EB) in a colossal magnetoresistance Nd2/3Ca1/3MnO3 manganite at low temperatures, evident of its intrinsic interface exchange coupling. The phenomenon found confirms our previous assumption that the low temperature magnetic structure of the compound is represented by small (nano-sized) ferromagnetic clusters immersed within the charge-ordered antiferromagnetic matrix. Magnetic behavior of the Nd2/3Ca1/3MnO3 perovskite at low temperature is consistent with its cluster-glass magnetic state originating from the self-organized phase separation. Slow relaxation of zero-field-cooled magnetization has been experimentally revealed as well. It confirms the cluster glass magnetic state of the compound.
BibTeX: @conference{Fertman201297, author = {Fertman, E. and Desnenko, V. and Dolya, S. and Kajnakova, M. and Feher, A.}, title = {Giant exchange bias in nano phase-segregated Nd2/3Ca 1/3MnO3}, journal = {International Conference on Oxide Materials for Electronic Engineering, OMEE 2012}, year = {2012}, pages = {97-98}, doi = {http://dx.doi.org/10.1109/OMEE.2012.6464784} }
Galetich I., Eremenko A., Pashchenko V., Sirenko V., Brook V.	The magnetic state of a single-crystal anion-excess manganite LaMnO 3+δ [Abstract] [BibTeX]	2012	Low Temperature Physics Vol. 38(6), pp. 499-502	DOI
Abstract: The magnetic moment of the LaMnO 3+δ single crystal was measured in a wide range of temperatures and magnetic fields under different cooling and measuring conditions. As a result, the nature of the magnetic state of LaMnO 3+δ was defined: spin glass clusters form in it.
BibTeX: @article{Galetich2012499, author = {Galetich, I.K. and Eremenko, A.V. and Pashchenko, V.A. and Sirenko, V.A. and Brook, V.V.}, title = {The magnetic state of a single-crystal anion-excess manganite LaMnO 3+δ}, journal = {Low Temperature Physics}, year = {2012}, volume = {38}, number = {6}, pages = {499-502}, doi = {http://dx.doi.org/10.1063/1.4723670} }
Galetich I., Eremenko A., Pashchenko V., Sirenko V., Brook V.	Nature of the magnetic phase transition in single-crystal LaMnO 3+δ [Abstract] [BibTeX]	2012	Low Temperature Physics Vol. 38(6), pp. 537-538	DOI
Abstract: The isotherms of the field dependences of the magnetic moment M(H) are measured at temperatures above and below the magnetic phase transition (T c = 125 K) in single-crystal lanthanum manganite with excess oxygen (LaMnO 3+δ). An analysis of these magnetic isotherms with Arrott plots and invoking the Banerjee criterion shows that the magnetic phase transition in this single crystal is a second order phase transition.
BibTeX: @article{Galetich2012537, author = {Galetich, I.K. and Eremenko, A.V. and Pashchenko, V.A. and Sirenko, V.A. and Brook, V.V.}, title = {Nature of the magnetic phase transition in single-crystal LaMnO 3+δ}, journal = {Low Temperature Physics}, year = {2012}, volume = {38}, number = {6}, pages = {537-538}, doi = {http://dx.doi.org/10.1063/1.4723680} }
Grechnev G., Panfilov A., Fedorchenko A., Desnenko V., Zhuravleva I., Gnatchenko S., Chareev D., Volkova O., Vasiliev A.	Electronic structure and magnetism of Fe-based superconductors [Abstract] [BibTeX]	2012	Ukrainian Journal of Physics Vol. 57(2), pp. 171-176	URL
Abstract: Ab initio calculations of the electronic structures are carried out for the novel FeSe1-xTex superconductors to explain the experimentally found anomalous magnetic properties in the normal state. The calculations have shown that FeSe1-xTex systems are close to a magnetic instability with dominating enhanced spin paramagnetism. The magnetic susceptibility is found to increase gradually with the Te content. The temperature dependences of the magnetic susceptibility χ and its anisotropy Δχ = χII - χ⊥ are investigated for FeSe, and a growth of the susceptibility with the temperature is revealed in the temperature range 4.2-300 K. For FeTe, a substantial increase of χ under pressure is found. The calculated paramagnetic susceptibility exhibits a strong dependence on the unit cell volume V and especially the height of chalcogen species from the Fe plane. The calculations have explained the experimental data on χ(T) and χ(P) for FeSe and FeTe, respectively.
BibTeX: @article{Grechnev2012171, author = {Grechnev, G.E. and Panfilov, A.S. and Fedorchenko, A.V. and Desnenko, V.A. and Zhuravleva, I.P. and Gnatchenko, S.L. and Chareev, D.A. and Volkova, O.S. and Vasiliev, A.N.}, title = {Electronic structure and magnetism of Fe-based superconductors}, journal = {Ukrainian Journal of Physics}, publisher = {National Academy of Sciences of Ukraine}, year = {2012}, volume = {57}, number = {2}, pages = {171-176}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84887072249&partnerID=40&md5=bc92a0b7f4d8a3be2d2bd60d5d8a334c} }
Grechnev G., Panfilov A., Fedorchenko A., Desnenko V., Gnatchenko S., Tsurkan V., Deisenhofer J., Loidl A., Chareev D., Volkova O., Vasiliev A.	Magnetic properties of novel FeSe(Te) superconductors [Abstract] [BibTeX]	2012	Journal of Magnetism and Magnetic Materials Vol. 324(21), pp. 3460-3463	DOI
Abstract: Magnetization studies were carried out for the novel FeSe 1-xTe x superconductors (0≤x≤1) to investigate a behavior of the intrinsic magnetic susceptibility χ in the normal state. The magnetic susceptibility was found to increase gradually with Te content. The temperature dependencies of the magnetic susceptibility χ and its anisotropy Δχ= χ∥- χ⊥ were measured for FeSe in the temperature range 4.2-300 K, and a growth of susceptibility with temperature was revealed. For FeTe a substantial increase of χ under pressure was found. Ab initio calculations of the band structure and magnetic susceptibility have shown, that FeSe 1-xTe x systems are close to magnetic instability with dominating enhanced spin paramagnetism. The calculated paramagnetic susceptibility exhibits a strong dependence on the unit cell volume V and especially the height of chalcogen species from the Fe plane. With appropriate values of these parameters the calculations have reproduced the experimental data on χ(T) and χ(P) for FeSe and FeTe, respectively.
BibTeX: @article{Grechnev20123460, author = {Grechnev, G.E. and Panfilov, A.S. and Fedorchenko, A.V. and Desnenko, V.A. and Gnatchenko, S.L. and Tsurkan, V. and Deisenhofer, J. and Loidl, A. and Chareev, D.A. and Volkova, O.S. and Vasiliev, A.N.}, title = {Magnetic properties of novel FeSe(Te) superconductors}, journal = {Journal of Magnetism and Magnetic Materials}, year = {2012}, volume = {324}, number = {21}, pages = {3460-3463}, doi = {http://dx.doi.org/10.1016/j.jmmm.2012.02.065} }
Grechnev G., Logosha A., Panfilov A., Zhuravleva I.	Effects of pressure on magnetic properties of gadolinium [Abstract] [BibTeX]	2012	Physica B: Condensed Matter Vol. 407(21), pp. 4143-4147	DOI
Abstract: Experimental and theoretical studies of pressure effects on magnetic properties and electronic structure of gadolinium metal were carried out to shed more light on the nature of magnetic ordering and interactions between the localized 4f moments. The dc paramagnetic susceptibility of Gd was measured in the temperature range 295-365 K and under hydrostatic pressure up to 0.16 GPa, yielding values of the paramagnetic Curie temperature Θ and its pressure derivative. Based on the results of ab initio electronic structure calculations, the experimental behavior of Θ under hydrostatic pressure together with the literature data on the uniform and uniaxial pressure effects was examined within a mean-field like approach. For this purpose, the effective d-band susceptibility and the relevant exchange integrals were calculated as functions of the lattice parameters within the density functional theory. These calculations provided a reasonable description of the experimentally observed uniform pressure effect, but a less satisfactory description of the uniaxial pressure effect.
BibTeX: @article{Grechnev20124143, author = {Grechnev, G.E. and Logosha, A.V. and Panfilov, A.S. and Zhuravleva, I.P.}, title = {Effects of pressure on magnetic properties of gadolinium}, journal = {Physica B: Condensed Matter}, year = {2012}, volume = {407}, number = {21}, pages = {4143-4147}, doi = {http://dx.doi.org/10.1016/j.physb.2012.06.038} }
Grechnev G., Logosha A., Panfilov A., Shitsevalova N.	Pressure effects on magnetic properties and electronic structure of EuB6 and GdB6 [Abstract] [BibTeX]	2012	Journal of Alloys and Compounds Vol. 511(1), pp. 5-8	DOI
Abstract: Experimental and theoretical studies of the pressure effects on magnetic properties and electronic structure of EuB6 and GdB6 compounds were carried out to shed light on the nature of their magnetic ordering. The magnetic susceptibility was measured under pressure up to 2 kbar at fixed temperatures of 78 and 300 K for the EuB6 and GdB 6 compounds, and also for the carbon doped EuB6, for comparison. The observed behavior of the paramagnetic Curie temperature Θ under pressure was analyzed within the RKKY-like approach based on the results of ab initio electronic structure calculations.
BibTeX: @article{Grechnev20125, author = {Grechnev, G.E. and Logosha, A.V. and Panfilov, A.S. and Shitsevalova, N.Y.}, title = {Pressure effects on magnetic properties and electronic structure of EuB6 and GdB6}, journal = {Journal of Alloys and Compounds}, year = {2012}, volume = {511}, number = {1}, pages = {5-8}, doi = {http://dx.doi.org/10.1016/j.jallcom.2011.08.068} }
Kajňaková M., Feher A., Fertman E., Desnenko V., Beznosov A., Dolya S.	Nanophase separation and magnetic spin glass in Nd2/3Ca 1/3MnO3 [Abstract] [BibTeX]	2012	Solid State Phenomena Vol. 190, pp. 675-678	DOI
Abstract: A study of the low temperature magnetic state of polycrystalline colossal magnetoresistance perovskite Nd2/3Ca1/3MnO3 has been carried out. The data obtained, such as strongly divergent ZFC and FC static magnetizations and frequency dependent ac susceptibility, are evident of the glassy magnetic state of the system. Well defined maxima Tmax in the in-phase linear ac susceptibility χ'curves were observed, indicating a spin-glass transition. Clear frequency dependence of the cusp temperature Tmax was found. The frequency dependence of Tmax was successfully analyzed by the dynamical scaling theory of a three-dimensional spin glass. Slow relaxation process and variety of relaxation times found imply a cluster glass magnetic state of the compound at low temperatures rather than a canonical spin glass state. The cluster glass state, accompanied by the multiple magnetic transitions of Nd2/3Ca1/3MnO3, might exist due to the competing interaction between the FM clusters and the AFM matrix induced by the complex nanophase segregated state of the compound.
BibTeX: @article{Kajnakova2012675, author = {Kajňaková, M. and Feher, A. and Fertman, E. and Desnenko, V. and Beznosov, A. and Dolya, S.}, title = {Nanophase separation and magnetic spin glass in Nd2/3Ca 1/3MnO3}, journal = {Solid State Phenomena}, publisher = {Trans Tech Publications Ltd}, year = {2012}, volume = {190}, pages = {675-678}, doi = {http://dx.doi.org/10.4028/www.scientific.net/SSP.190.675} }
Lukienko I., Kharchenko N., Khrustalev V., Savytskiy V., Fedorchenko A., Desnenko V., Stetsenko A., Zorchenko V.	Reduction of superparamagnetic clusters in the [Co/Cu(111)] n nanofilms, induced by the quantum size effect [Abstract] [BibTeX]	2012	Low Temperature Physics Vol. 38(9), pp. 848-853	DOI
Abstract: It is known that the quantum size effects are important for the formation of morphological properties of metal films. The regularities in the behavior of the superparamagnetic magnetoresistive effect in multilayer nanofilms Co/Cu(111) in a magnetic field, found in the work, indicate the influence of the electron size effect on the formation of clusters in these films. The results of measurements of the high-field magnetoresistive effect are reported for multilayer films [Co/Cu(111)]20 with a constant thickness of cobalt layers and the thickness of copper layer varying from film to film. It is found that an effective size of superparamagnetic formations is reduced in the films with thickness of the copper layers corresponding to the maxima of the antiferromagnetic exchange coupling between cobalt layers. It is suggested that the observed "grinding" of superparamagnetic particles is caused by oscillating changes in the electron density in the interface layer Co/Cu, induced by electron quantum size effect in the copper layers.
BibTeX: @article{Lukienko2012848, author = {Lukienko, I.N. and Kharchenko, N.F. and Khrustalev, V.M. and Savytskiy, V.N. and Fedorchenko, A.V. and Desnenko, V.A. and Stetsenko, A.N. and Zorchenko, V.V.}, title = {Reduction of superparamagnetic clusters in the [Co/Cu(111)] n nanofilms, induced by the quantum size effect}, journal = {Low Temperature Physics}, year = {2012}, volume = {38}, number = {9}, pages = {848-853}, doi = {http://dx.doi.org/10.1063/1.4752100} }
Pluzhnikov V., Nizhankovskii V., Ievdokimova A., Shitsevalova N.	De Haas-van Alphen effect, magnetization, magnetoresistance and magnetostriction of GdB 4 as compared with TmB 4 [Abstract] [BibTeX]	2012	European Physical Journal B Vol. 85(8), pp. 251	DOI
Abstract: De Haas-van Alphen (dHvA) effect measurements were performed on GdB 4 single crystal (R 300 K/R 4.2K ≈ 12) in AFM state from 1.5 to 4.2 K in magnetic fields up to 14 T. 12 main branches of the oscillations were observed in the frequency range (0.1 ÷ 28) × 10 2 T. The angular dependence of the dHvA spectrum suggests a strongly anisotropic Fermi surface. Corresponding cyclotron masses m c * are light, ranging from 0.2 to 0.8 m0. We studied additionally the magnetization of GdB 4, linear and volume magnetostriction, and magnetoresistance of GdB 4 in comparison with the same properties of TmB 4 single crystal above 1.5 K in the field of 0 ÷ 14 T. At 4.2 K and H ∥ 〈110〈 collinear to the GdB 4 easy magnetization axis the volume magnetostriction revealed the lattice contraction with the field rise excluding the range of H ≈ (11 ÷ 13) T, where the lattice expansion is accompanied by a sharp magnetization increase due to the destruction of its non-collinear magnetic structure. The magnetostricive behavior in GdB 4 and TmB 4 is different due to the CEF effect.
BibTeX: @article{Pluzhnikov2012, author = {Pluzhnikov, V. and Nizhankovskii, V.I. and Ievdokimova, A. and Shitsevalova, N.}, title = {De Haas-van Alphen effect, magnetization, magnetoresistance and magnetostriction of GdB 4 as compared with TmB 4}, journal = {European Physical Journal B}, year = {2012}, volume = {85}, number = {8}, pages = {251}, doi = {http://dx.doi.org/10.1140/epjb/e2012-20636-y} }
Polishchuk D., Tovstolytkin A., Fertman E., Desnenko V., Beznosov A., Kajňaková M., Feher A.	Structural first-order transformation in La 2/3Ba 1/3MnO 3: ESR study [Abstract] [BibTeX]	2012	Journal of Magnetism and Magnetic Materials Vol. 324(24), pp. 4225-4230	DOI
Abstract: We have studied by the electron-spin resonance (ESR) and static magnetic field techniques, the La 2/3Ba 1/3MnO 3 perovskite, which was previously shown to exhibit a martensitic phase transformation in the vicinity of T s∼200 K [Physical Review B 68, 054109 (2003)], leading to its structural phase-segregated state. Resonant absorptions reveal that in the temperature interval from 100 K to 340 K the compound represents a mixture of two ferromagnetic phases possessing different magnetizations, in varying proportions depending on the temperature, and a small amount of a paramagnetic phase. The results agree well with the previous neutron diffraction study. Applied in the ESR experiments, magnetic fields (2-6 kOe) strongly affect the magnetization curves: even magnetic field as high as 700 Oe modifies the anomaly in the phase transformation region and removes the difference between the zero-field cooled and field-cooled magnetization curves, which implies that the difference in the magnetic susceptibility of the coexisting phases is small and the magnetic domain configuration can be easily changed.
BibTeX: @article{Polishchuk20124225, author = {Polishchuk, D.M. and Tovstolytkin, A.I. and Fertman, E. and Desnenko, V. and Beznosov, A. and Kajňaková, M. and Feher, A.}, title = {Structural first-order transformation in La 2/3Ba 1/3MnO 3: ESR study}, journal = {Journal of Magnetism and Magnetic Materials}, year = {2012}, volume = {324}, number = {24}, pages = {4225-4230}, doi = {http://dx.doi.org/10.1016/j.jmmm.2012.07.054} }
Sirenko V.	Critical phenomena in superconductors and uniaxial antiferromagnets (Review Article) [Abstract] [BibTeX]	2012	Low Temperature Physics Vol. 38(9), pp. 799-806	DOI
Abstract: This overview is inspired by the pioneering works by Eremenko et al. on the first observed similarities in the low-temperature phase formation of conventional antiferromagnets and superconductors near the critical temperature of the transition. In the development of the detected similarities, a comparison was made of the temperature dependence of the magnetic and structural properties of new anisotropic superconductors and antiferromagnets with competing order parameters (multiferroics). Common features in their critical behavior near the ordering temperature Tc are discussed.
BibTeX: @article{Sirenko2012799, author = {Sirenko, V.A.}, title = {Critical phenomena in superconductors and uniaxial antiferromagnets (Review Article)}, journal = {Low Temperature Physics}, year = {2012}, volume = {38}, number = {9}, pages = {799-806}, doi = {http://dx.doi.org/10.1063/1.4752222} }
Troyanchuk I., Bushinsky M., Karpinsky D., Sirenko V.	Antiferromagnet-ferromagnet transitions in cobaltites [Abstract] [BibTeX]	2012	Low Temperature Physics Vol. 38(7), pp. 662-668	DOI
Abstract: Three series of oxygen-deficient cobaltites, La0.5Ba0.5CoO3-δ, LnBaCo2O5.5 and Sr2YCo4O10.5, have been studied. La0.5Ba0.5CoO3 is an insulating ferromagnet whereas La0.5Ba0.5CoO2.75 is a pure antiferromagnet in which the oxygen vacancies are disordered. The ordering of the oxygen vacancies leads to the appearance of a ferromagnetic component, apparently because of the formation of a noncollinear magnetic structure. The antiferromagnet-"ferromagnet" transition is accompanied by a giant magnetoresistance. It is suggested that in the ferromagnetic oxidized compounds, the Co3+ and Co4+ ions adopt intermediate spin states, whereas in the antiferromagnetic (Co4+-free) compositions, the Co3+ ions have a high-spin state (CoO5 pyramids) with a dominant low-spin state (CoO6 octahedra). In both the ferromagnetic and antiferromagnetic compounds, superexchange via oxygen plays an essential role in determining the magnetic properties.
BibTeX: @article{Troyanchuk2012662, author = {Troyanchuk, I.O. and Bushinsky, M.V. and Karpinsky, D.V. and Sirenko, V.A.}, title = {Antiferromagnet-ferromagnet transitions in cobaltites}, journal = {Low Temperature Physics}, year = {2012}, volume = {38}, number = {7}, pages = {662-668}, doi = {http://dx.doi.org/10.1063/1.4736615} }
Zvyagina G., Zhekov K., Bilych I., Zvyagin A., Gudim I., Temerov V.	Magnetic phase transitions in the NdFe 3(BO 3) 4 multiferroic [Abstract] [BibTeX]	2012	Low Temperature Physics Vol. 37(12), pp. 1010-1020	DOI
Abstract: Low-temperature studies of the behavior of the sound velocity and attenuation of acoustic modes have been performed on a single crystal NdFe 3(BO 3) 4 Transitions of the magnetic subsystem to the antiferromagnetically ordered state at T N ≈ 30.6 K have been revealed in the temperature behavior of the elastic characteristics. The features in the temperature behavior of elastic characteristics of the neodymium ferroborate and its behavior in the external magnetic field, applied in the basic plane of the crystal, permit us to suppose that the transition to an incommensurate spiral phase is realized in the system. This phase transition behaves as the first order one. H-T phase diagrams for the cases H ∥ a and H ∥ b have been constructed. The phenomenological theory, which explains observed features, has been developed.
BibTeX: @article{Zvyagina20121010, author = {Zvyagina, G.A. and Zhekov, K.R. and Bilych, I.V. and Zvyagin, A.A. and Gudim, I.A. and Temerov, V.L.}, title = {Magnetic phase transitions in the NdFe 3(BO 3) 4 multiferroic}, journal = {Low Temperature Physics}, year = {2012}, volume = {37}, number = {12}, pages = {1010-1020}, doi = {http://dx.doi.org/10.1063/1.3674182} }
Zvyagina G., Zhekov K., Zvyagin A., Gudim I., Bilych I.	Magnetic anisotropy in the basal plane of the rare-earth ferroborate Nd 0.75Dy 0.25Fe 3(BO 3) 4 [Abstract] [BibTeX]	2012	Low Temperature Physics Vol. 38(5), pp. 446-449	DOI
Abstract: The magneto-acoustic behavior of the rare-earth multiferroic Nd 0.75Dy 0.25Fe 3(BO 3) 4 in external magnetic fields lying in the basal plane of the crystal is studied. The data confirm the existence of a magnetic anisotropy in this plane and of magnetic phase transitions in the crystal caused by this anisotropy. H-T phase diagrams are constructed for the cases H∥C 2 and H⊥C 2.
BibTeX: @article{Zvyagina2012446, author = {Zvyagina, G.A. and Zhekov, K.R. and Zvyagin, A.A. and Gudim, I.A. and Bilych, I.V.}, title = {Magnetic anisotropy in the basal plane of the rare-earth ferroborate Nd 0.75Dy 0.25Fe 3(BO 3) 4}, journal = {Low Temperature Physics}, year = {2012}, volume = {38}, number = {5}, pages = {446-449}, doi = {http://dx.doi.org/10.1063/1.4707947} }
Grechnev G.E., Panfilov A.S., Desnenko V.A., Fedorchenko A.V., Zhuravleva I.P., Gnatchenko S.L., Tsurkan V., Chareev D.A., Kozlyakova E.S., Volkova O.S., Vasiliev A.N.	Pressure effects on electronic structure and magnetic properties of the FeSe(Te) superconductors [Abstract] [BibTeX]	2012	High Pressure Physics and Technics Vol. 22(4), pp. 28-38	URL
Abstract: The magnetic susceptibility χ of the FeSe and FeTe compounds, which form the simplest FeSe(Te) system of the novel iron-based superconductors, is studied in the normal state under hydrostatic pressure. A substantial positive pressure effect on χ is detected at low temperatures for both compounds. At room temperature, this effect is found to be also strong, but it is negative for FeSe and positive for FeTe. Ab initio calculations of the pressure dependent electronic structure and magnetic susceptibility indicate that FeSe and FeTe are close to magnetic instability with dominating enhanced spin paramagnetism. The calculated paramagnetic susceptibility exhibits a strong dependence on the unit cell volume and the height Z of chalcogen species from the Fe plane. The observed large positive pressure effects on χ in FeTe and FeSe at low temperatures are related to considerable sensitivity of the paramagnetism to the internal parameter Z. It is shown that available experimental data on the strong and nonmonotonic pressure dependence of the superconducting transition temperature in FeSe correlate qualitatively with the calculated behavior of the density of electronic states at the Fermi level.
BibTeX: @article{grechnev2012iii, author = {Grechnev, G. E. and Panfilov, A. S. and Desnenko, V. A. and Fedorchenko, A. V. and Zhuravleva, I. P. and Gnatchenko, S. L. and Tsurkan, V. and Chareev, D. A. and Kozlyakova, E. S. and Volkova, O. S. and Vasiliev, A. N.}, title = {Pressure effects on electronic structure and magnetic properties of the FeSe(Te) superconductors}, journal = {High Pressure Physics and Technics}, year = {2012}, volume = {22}, number = {4}, pages = {28-38}, url = {http://www.fti.dn.ua/site/wp-content/uploads/2014/02/2012_4_3.pdf} }
Avramenko Y., Bezuglyi E., Burma N., Fil V.	Electric potential of the electron sound wave: Sharp disappearance in the superconducting state [Abstract] [BibTeX]	2011	Physical Review B - Condensed Matter and Materials Physics Vol. 84(21), pp. 214504	DOI
Abstract: We study the ac electric potential induced by the electron sound wave (a perturbation of the electron distribution function propagating with the Fermi velocity) in single crystals of high-purity gallium. The potential and the elastic components of the electron sound demonstrate qualitatively different dependencies on the electron relaxation rate: while the phase of the potential increases with temperature, the phase of elastic displacement decreases. This effect is explained within the multiband model, in which the potential is attributed to the ballistic quasiwave, while the elastic component is associated with the zero-sound wave. We observed a mysterious property of the superconducting state: all manifestations of the potential accompanying the lattice deformations, including usual sound wave, disappear below T c in almost jumplike manner.
BibTeX: @article{Avramenko2011, author = {Avramenko, Y.A. and Bezuglyi, E.V. and Burma, N.G. and Fil, V.D.}, title = {Electric potential of the electron sound wave: Sharp disappearance in the superconducting state}, journal = {Physical Review B - Condensed Matter and Materials Physics}, year = {2011}, volume = {84}, number = {21}, pages = {214504}, doi = {http://dx.doi.org/10.1103/PhysRevB.84.214504} }
Beznosov A., Fertman E., Desnenko V., Kajňaková M., Feher A.	The NdMn exchange interaction, low temperature specific heat and magnetism of Nd2/3Ca1/3MnO3 [Abstract] [BibTeX]	2011	Journal of Magnetism and Magnetic Materials Vol. 323(18-19), pp. 2380-2385	DOI
Abstract: The low temperature specific heat and magnetic characteristics of Nd 2/3Ca1/3MnO3 perovskite are studied in a wide range of magnetic fields (up to 9 T). Temperature dependent specific heat data show a broadened Schottky-like anomaly below 20 K caused by splitting of the Nd3 ions ground-state doublet in the effective molecular field H ex, determined by exchange interaction between Nd and Mn spin systems supplemented by an applied external magnetic field. Existence of the splitting at zero magnetic field and expressed field dependence is the evidence of a strong exchange coupling between Nd and Mn magnetic subsystems. The Nd-ions magnetic ordering leads to an additional contribution to the magnetic moment of the system below 30 K, producing anomalies of the magnetic loss and field-cooled and zero-field-cooled magnetizations. The observed broadened Schottky-like anomalies are fitted for each applied magnetic field by the sum of three Schottky functions. Applied magnetic field extends the anomaly region and shifts it to higher temperatures. Splitting of the higher crystal field Kramers doublets gives an additional contribution to the heat capacity in magnetic fields. The ground state doublet g-factors g\|\| and g⊥ were estimated to be 3.4 and 2.2, respectively, and Hex was estimated to be 9 T. The Nd3 ions magnetic moment estimated from the magnetization data agrees with the value obtained from the specific heat data.
BibTeX: @article{Beznosov20112380, author = {Beznosov, A. and Fertman, E. and Desnenko, V. and Kajňaková, M. and Feher, A.}, title = {The NdMn exchange interaction, low temperature specific heat and magnetism of Nd2/3Ca1/3MnO3}, journal = {Journal of Magnetism and Magnetic Materials}, year = {2011}, volume = {323}, number = {18-19}, pages = {2380-2385}, doi = {http://dx.doi.org/10.1016/j.jmmm.2011.05.001} }
Bosin M., Desnenko V., Nikiforenko V.	On a possible mechanism of instability of plastic deformation of metals and alloys at 4.2 K [Abstract] [BibTeX]	2011	Journal of Engineering Physics and Thermophysics Vol. 84(2), pp. 445-450	DOI
Abstract: The fine structure of spontaneous deformation jumps and jumps initiated by both the shock action on a deformation device and a strong fast-changing magnetic field (up to 2.7 MA/m) has been investigated in metals and alloys at liquid-helium temperatures. Oscillography of the signals of changes in the load on the sample and of acoustic emission has made it possible to reveal the relationship between types of jumps and postulate on the mechanism of their appearance.
BibTeX: @article{Bosin2011445, author = {Bosin, M.E. and Desnenko, V.A. and Nikiforenko, V.N.}, title = {On a possible mechanism of instability of plastic deformation of metals and alloys at 4.2 K}, journal = {Journal of Engineering Physics and Thermophysics}, publisher = {Springer New York LLC}, year = {2011}, volume = {84}, number = {2}, pages = {445-450}, doi = {http://dx.doi.org/10.1007/s10891-011-0491-y} }
Dalakova N., Belevtsev B., Panfilov A., Belyaev E.	Temperature behavior of conductivity in a La2CuO 4 + δ single crystal upon the paramagnetic-antiferromagnetic transition [Abstract] [BibTeX]	2011	Bulletin of the Russian Academy of Sciences: Physics Vol. 75(5), pp. 692-694	DOI
Abstract: The temperature dependence of the resistance of a La2CuO 4 + δ (δ ≈ 0.05) single crystal with the Neel temperature T N ≈ 205 K was investigated in order to establish the correlation between the transport and magnetic properties of the crystal. The R(T) dependence near T N reveals a kink related to the enhancement of sample's conductivity upon the transition from the antiferromagnetic to paramagnetic state. With an increase in temperature far above T N, the transition from the dielectric (dR/dT < 0) to metal (dR/dT > 0) occurs. The observed behavior of resistance is attributed to delocalization of carriers above T N.
BibTeX: @article{Dalakova2011692, author = {Dalakova, N.V. and Belevtsev, B.I. and Panfilov, A.S. and Belyaev, E.Yu.}, title = {Temperature behavior of conductivity in a La2CuO 4 + δ single crystal upon the paramagnetic-antiferromagnetic transition}, journal = {Bulletin of the Russian Academy of Sciences: Physics}, year = {2011}, volume = {75}, number = {5}, pages = {692-694}, doi = {http://dx.doi.org/10.3103/S1062873811050133} }
Fedorchenko A., Grechnev G., Desnenko V., Panfilov A., Gnatchenko S., Tsurkan V., Deisenhofer J., Loidl A., Volkova O., Vasiliev A.	Pressure effects on the magnetic susceptibility of FeTex (x ≃ 1.0 ) [Abstract] [BibTeX]	2011	Journal of Physics Condensed Matter Vol. 23(32), pp. 325701	DOI
Abstract: The magnetic susceptibility χ of FeTex compounds () was studied under hydrostatic pressure up to 2kbar at fixed temperatures of 55, 78 and 300K. Measurements were taken both for polycrystalline and single crystalline samples. At ambient pressure, with decreasing temperature a drastic drop in χ(T) was confirmed at K, which appears to be closely related to antiferromagnetic ordering. The obtained results have revealed a puzzling growth of susceptibility under pressure, and this effect is enhanced by lowering the temperature. To shed light on the pressure effects in the magnetic properties of FeTe, abinitio calculations of its volume dependent band structure and the exchange enhanced paramagnetic susceptibility were performed within the local spin density approximation.
BibTeX: @article{Fedorchenko2011, author = {Fedorchenko, A.V. and Grechnev, G.E. and Desnenko, V.A. and Panfilov, A.S. and Gnatchenko, S.L. and Tsurkan, V. and Deisenhofer, J. and Loidl, A. and Volkova, O.S. and Vasiliev, A.N.}, title = {Pressure effects on the magnetic susceptibility of FeTex (x ≃ 1.0 )}, journal = {Journal of Physics Condensed Matter}, year = {2011}, volume = {23}, number = {32}, pages = {325701}, doi = {http://dx.doi.org/10.1088/0953-8984/23/32/325701} }
Fedorchenko A., Grechnev G., Desnenko V., Panfilov A., Gnatchenko S., Tsurkan V., Deisenhofer J., Krug von Nidda H.-A., Loidl A., Chareev D., Volkova O., Vasiliev A.	Magnetic and superconducting properties of FeSe1-xTex (x∼0, 0.5, and 1.0) [Abstract] [BibTeX]	2011	Low Temperature Physics Vol. 37(1), pp. 83-89	DOI
Abstract: The magnetization of FeSe1-xTex (x∼0, 0.5, and 1.0) compounds has been studied in magnetic fields up to 50kOe and at temperatures of 2-300K. The superconducting transition was observed at Tc∼8K and 13.6-14.2K in FeSe0.963 and FeSe0.5Te0.5, respectively. For most of the samples, nonlinearity of the magnetization curves in the normal state gives evidence of a common, substantial presence of ferromagnetic impurities in these compounds. By taking these impurity effects into account, the intrinsic magnetic susceptibility χ of FeSe0.963, FeSe0.5Te0.5, and FeTe was estimated to increase gradually with Te content. For FeTe a drastic drop in χ(T) with decreasing temperature was found at TN∼70K, which is presumably related to antiferromagnetic ordering. To shed light on the observed magnetic properties, ab initio calculations of the exchange enhanced magnetic susceptibility are performed for FeSe and FeTe in the local spin density approximation.
BibTeX: @article{Fedorchenko201183, author = {Fedorchenko, A.V. and Grechnev, G.E. and Desnenko, V.A. and Panfilov, A.S. and Gnatchenko, S.L. and Tsurkan, V.V. and Deisenhofer, J. and Krug von Nidda, H.-A. and Loidl, A. and Chareev, D.A. and Volkova, O.S. and Vasiliev, A.N.}, title = {Magnetic and superconducting properties of FeSe1-xTex (x∼0, 0.5, and 1.0)}, journal = {Low Temperature Physics}, year = {2011}, volume = {37}, number = {1}, pages = {83-89}, doi = {http://dx.doi.org/10.1063/1.3552132} }
Feher A., Dolya S., Fertman E., Kajňaková M., Desnenko V., Šebek J., Šantavá E.	Analysis of the low temperature magnetic contributions to the specific heat of (Nd x Y 1-x ) 2/3Ca 1/3MnO 3 (x=0, 0.1) [Abstract] [BibTeX]	2011	Journal of Low Temperature Physics Vol. 162(5-6), pp. 529-535	DOI
Abstract: The low temperature specific heat of the colossal magnetoresistance compounds (Nd x Y 1-x ) 2/3Ca 1/3MnO 3 (x=0, 0.1) for 0.4≤T<2 K in magnetic fields up to H=9 T has been studied. Applied magnetic fields lead to the drop of the low temperature specific heat by more than 2 orders, which implies a large magnetic contribution. Experimental data were successfully fitted by the sum of the hyperfine C hyp, the linear T-dependent C sg and the spin waves C sw contributions. The C sg attributed to the glassy state of the magnetic systems of the studied insulating compounds exponentially decreases with the increase of H up to ∼5 T. The C sw providing the best fitting of the experimental data is attributed to the ferromagnetic spin waves with pseudo gap Δ(H) in the spin-wave spectrum which increases linearly with the increase of the applied magnetic field. The Δ(0)∼0.8 K is approximately the same for both compounds studied.
BibTeX: @article{Feher2011529, author = {Feher, A. and Dolya, S. and Fertman, E. and Kajňaková, M. and Desnenko, V. and Šebek, J. and Šantavá, E.}, title = {Analysis of the low temperature magnetic contributions to the specific heat of (Nd x Y 1-x ) 2/3Ca 1/3MnO 3 (x=0, 0.1)}, journal = {Journal of Low Temperature Physics}, year = {2011}, volume = {162}, number = {5-6}, pages = {529-535}, doi = {http://dx.doi.org/10.1007/s10909-010-0291-3} }
Grechnev G., Logosha A., Panfilov A., Kuchin A., Vasijev A.	Effect of pressure on the magnetic properties of YNi5, LaNi5, and CeNi5 [Abstract] [BibTeX]	2011	Low Temperature Physics Vol. 37(2), pp. 138-143	DOI
Abstract: The effect of pressure on the electronic structure and magnetic properties of the compounds YNi5, LaNi5, and CeNi5 is studied. Large magnetovolume effects of magnitude dlnχ/dlnV≃4-7 are found for the magnetic susceptibility χ of these systems at low temperatures. Experimental data and "first principles" calculations of the electronic structure and paramagnetic contributions to the susceptibility indicate that YNi5, LaNi5, and CeNi5 are close to a quantum critical point. It is found that the van Vleck orbital contribution to the magnetic susceptibility is 15-20% in these exchange-enhanced paramagnetic materials and should be taken into account in analyzing experimental data on χ and dlnχ/dlnV. Calculations of the magnetic-field induced moments for atoms in the unit cell of YNi5 reveal an inhomogeneous distribution of the magnetization density and a nontrivial competition between the spin and orbital moments.
BibTeX: @article{Grechnev2011138, author = {Grechnev, G.E. and Logosha, A.V. and Panfilov, A.S. and Kuchin, A.G. and Vasijev, A.N.}, title = {Effect of pressure on the magnetic properties of YNi5, LaNi5, and CeNi5}, journal = {Low Temperature Physics}, year = {2011}, volume = {37}, number = {2}, pages = {138-143}, doi = {http://dx.doi.org/10.1063/1.3555874} }
Grechnev G., Desnenko V., Fedorchenko A., Panfilov A., Prylutskyy Y., Grybova M., Matzui L., Ritter U., Scharff P., Kolesnichenko Y.	Magnetic properties of multi-walled carbon nanotubes modified with cobalt [Abstract] [BibTeX]	2011	Materialwissenschaft und Werkstofftechnik Vol. 42(1), pp. 29-32	DOI
Abstract: Magnetic properties of multi-walled carbon nanotubes (MWCNT) modified with cobalt were studied in detail in the temperature range (4.2-290) K. MWCNT which encapsulate Co nanoparticles were obtained using CVD methods. The low temperature SQUID magnetization measurements were supplemented by structural investigations with thermogravimetric analysis, HRTEM and SEM.
BibTeX: @article{Grechnev201129, author = {Grechnev, G.E. and Desnenko, V.A. and Fedorchenko, A.V. and Panfilov, A.S. and Prylutskyy, Y.I. and Grybova, M.I. and Matzui, L.Y. and Ritter, U. and Scharff, P. and Kolesnichenko, Y.A.}, title = {Magnetic properties of multi-walled carbon nanotubes modified with cobalt}, journal = {Materialwissenschaft und Werkstofftechnik}, year = {2011}, volume = {42}, number = {1}, pages = {29-32}, doi = {http://dx.doi.org/10.1002/mawe.201100725} }
Grechnev G., Logosha A., Panfilov A., Svechkarev I., Musil O., Svoboda P.	Effect of pressure on magnetic properties of the fluctuating-valence system Ce(Ni 1-xCu x)5 [Abstract] [BibTeX]	2011	Low Temperature Physics Vol. 37(10), pp. 847-851	DOI
Abstract: The magnetic susceptibility X of isostructural Ce(Ni 1-xCu x)5 alloys (0 ≤ x ≤ 0.9) is studied as a function of hydrostatic pressure up to 2 kbar for fixed temperatures of 77.3 and 300 K. The pronounced effect of pressure on the susceptibility is negative in sign and depends nonmonotonically on the Cu content, with a sharp maximum at x ~ 0.4. The experimental results are discussed in terms of a valence instability of Ce ions in these alloys. The major contributions to χ and their volume dependences are calculated ab initio in a local spin density approximation for the reference compound CeNi 5, and appear to be in close agreement with experimental data.
BibTeX: @article{Grechnev2011847, author = {Grechnev, G.E. and Logosha, A.V. and Panfilov, A.S. and Svechkarev, I.V. and Musil, O. and Svoboda, P.}, title = {Effect of pressure on magnetic properties of the fluctuating-valence system Ce(Ni 1-xCu x)5}, journal = {Low Temperature Physics}, year = {2011}, volume = {37}, number = {10}, pages = {847-851}, doi = {http://dx.doi.org/10.1063/1.3671862} }
Karachevtsev V., Stepanian S., Glamazda A., Karachevtsev M., Eremenko V., Lytvyn O., Adamowicz L.	Noncovalent interaction of single-walled carbon nanotubes with 1-pyrenebutanoic acid succinimide ester and glucoseoxidase [Abstract] [BibTeX]	2011	Journal of Physical Chemistry C Vol. 115(43), pp. 21072-21082	DOI
Abstract: Peculiarities of the interface interactions of 1-pyrenebutanoic acid N-hydroxysuccinimide ester (PSE) with single-walled carbon nanotubes (SWCNTs) and enzyme glucoseoxidase (GOX) have been studied with the resonance Raman spectroscopy and theoretical calculations employing the DFT method and the molecular dynamics (MD) simulation. The interaction of a nanotube with PSE leads to a downshift of the band assigned in the Raman spectrum to the tangential mode of the hybrid with respect to the position of this mode in the spectrum of the pristine SWCNT. The MD simulation demonstrates that the direct interaction between SWCNT and GOX is very strong. This interaction can be expected to change the structure of the enzyme and to significantly affect its activity. The MD simulation also shows that only one PSE molecule used as a linker between SWCNT and GOX is enough to keep GOX near the nanotube surface in the water surrounding and to prevent strong interaction between SWCNT and GOX. However, to stabilize this nanobiohybrid in water at least two PSE linkers are needed. The molecular structure of PSE is determined using the density functional theory approach (DFT/B3LYP/6-31++G(d,p). The geometries and the relative stabilities of all possible PSE conformers are characterized in the calculations. High structural flexibility of the PSE molecule is demonstrated. Calculations (at the M05-2X level of theory) have also been performed on the structures and the interaction energies of complexes formed by various SWCNTs with PSE and pyrene. Pyrene interacts strongly with the surface of carbon nanotubes with different chiralities, but the interaction with zigzag nanotubes is stronger than with armchair ones of the same diameter. Increasing the diameter of the SWCNTs leads to a higher adsorption energy, reaching the maximum value for graphene (-20.8 kcal/mol).
BibTeX: @article{Karachevtsev201121072, author = {Karachevtsev, V.A. and Stepanian, S.G. and Glamazda, A.Y. and Karachevtsev, M.V. and Eremenko, V.V. and Lytvyn, O.S. and Adamowicz, L.}, title = {Noncovalent interaction of single-walled carbon nanotubes with 1-pyrenebutanoic acid succinimide ester and glucoseoxidase}, journal = {Journal of Physical Chemistry C}, year = {2011}, volume = {115}, number = {43}, pages = {21072-21082}, doi = {http://dx.doi.org/10.1021/jp207916d} }
Len T., Matzui L., Ovsienko I., Prylutskyy Y., Andrievskii V., Berkutov I., Grechnev G., Kolesnichenko Y.	Magnetoresistance of nanocarbon materials based on carbon nanotubes [Abstract] [BibTeX]	2011	Low Temperature Physics Vol. 37(10), pp. 819-823	DOI
Abstract: The results of experimental investigations of magnetoresistance in nanocarbon material (NCM) containing carbon nanotubes in magnetic field up to 5 T and at temperature up to 0.54 K are reported. The obtained experimental magnetoresistance curves of NCM are described satisfactorily within the framework of the shrinkage effect of wave function of localized state in a magnetic field along with the spin-polarization mechanism.
BibTeX: @article{Len2011819, author = {Len, T.A. and Matzui, L.Y. and Ovsienko, I.V. and Prylutskyy, Y.I. and Andrievskii, V.V. and Berkutov, I.B. and Grechnev, G.E. and Kolesnichenko, Y.A.}, title = {Magnetoresistance of nanocarbon materials based on carbon nanotubes}, journal = {Low Temperature Physics}, year = {2011}, volume = {37}, number = {10}, pages = {819-823}, doi = {http://dx.doi.org/10.1063/1.3665770} }
Ritter U., Scharff P., Grechnev G., Desnenko V., Fedorchenko A., Panfilov A., Prylutskyy Y., Kolesnichenko Y.	Structure and magnetic properties of multi-walled carbon nanotubes modified with cobalt [Abstract] [BibTeX]	2011	Carbon Vol. 49(13), pp. 4443-4448	DOI
Abstract: The magnetic properties of multi-walled carbon nanotubes (MWCNTs) modified with cobalt nanoparticles were studied in the temperatures and magnetic field range of (4.2-290) K and (0.03-5) T, respectively. Nanoparticles of cobalt encapsulated inside MWCNTs were obtained by using the chemical vapor deposition technique. The low temperature SQUID magnetization measurements were supplemented with structural investigations by means of high-resolution transmission electron microscopy, scanning electron microscopy as well as thermogravimetric and X-ray diffraction analysis. X-ray diffraction revealed the presence of MWCNTs, f.c.c. Co and h.c.p. Co phases. The magnetic characterization provided the remanent magnetization value (MR) of about 0.07 emu/g (∼40% of the saturation moment), while the coercive field (HC) value amounts to 600 Oe. Both parameters MR and HC slightly decrease with the rise of temperature. The substantial magnetization increase observed at low temperatures suggests the existence of nano Co clusters (in the atomic scale size).
BibTeX: @article{Ritter20114443, author = {Ritter, U. and Scharff, P. and Grechnev, G.E. and Desnenko, V.A. and Fedorchenko, A.V. and Panfilov, A.S. and Prylutskyy, Yu.I. and Kolesnichenko, Yu.A.}, title = {Structure and magnetic properties of multi-walled carbon nanotubes modified with cobalt}, journal = {Carbon}, year = {2011}, volume = {49}, number = {13}, pages = {4443-4448}, doi = {http://dx.doi.org/10.1016/j.carbon.2011.06.039} }
Troyanchuk I., Karpinsky D., Bushinsky M., Kovetskaya M., Efimova E., Eremenko V.	Morphotropic phase boundary, weak ferromagnetism, and strong piezoelectric effect in Bi 1-xCa xFeO 3-x/2 compounds [Abstract] [BibTeX]	2011	Journal of Experimental and Theoretical Physics Vol. 113(6), pp. 1025-1031	DOI
Abstract: The crystal structure and magnetic and piezoelectric properties of the Bi 1-xCa xFeO 3-x/2 system (x ≤ 0.2) are studied. The crystal-structure transformations occur in the following sequence: rhombohedral (R3c) polar phase (x ≤ 0.06) → modulated polar phase (0.07 ≤ x ≤ 0.1) → modulated antipolar phase (0.11 ≤ x ≤ 0.14). The modulated polar and antipolar phases are weakly ferromagnetic with a spontaneous magnetization of 0.25 G cm 3/g (x = 0.09). In the polar weak ferromagnet with x = 0.09, a uniform piezoelectric response 2.5 times stronger than in the initial BiFeO 3 compound is detected by the piezoelectric force microscopy.
BibTeX: @article{Troyanchuk20111025, author = {Troyanchuk, I.O. and Karpinsky, D.V. and Bushinsky, M.V. and Kovetskaya, M.I. and Efimova, E.A. and Eremenko, V.V.}, title = {Morphotropic phase boundary, weak ferromagnetism, and strong piezoelectric effect in Bi 1-xCa xFeO 3-x/2 compounds}, journal = {Journal of Experimental and Theoretical Physics}, year = {2011}, volume = {113}, number = {6}, pages = {1025-1031}, doi = {http://dx.doi.org/10.1134/S1063776111140196} }
Bartolomé E., Bartolomé J., Arauzo A., Eremenko V., Sirenko V.	AC response of 2H-NbSe2 single crystals with electron-irradiation-induced defects [Abstract] [BibTeX]	2010	Journal of Physics Condensed Matter Vol. 22(29), pp. 295702	DOI
Abstract: The generation of defects in NbSe2 single crystals by electron irradiation has been investigated by a combination of ac susceptibility and structural measurements. Remarkably, thanks to the layered structure of NbSe2, we show that electronic irradiation cannot only create point defects but also in-plane extended defects, which modify anisotropically the ac response. Indeed, the analysis of the onset of the nonlinear susceptibility response, Hacl(T), as a function of irradiation dose and field orientation shows a correlated increase in the density of anisotropic defects induced by electron irradiation. Also, we measured a decrease in the strength of the pinning (Labusch) constant αL accounting for elastic vortex oscillations within the linear Campbell regime for high-dose-irradiated samples in a transverse field, again compatible with the presence of planar defects hindering vortex pinning. X-ray powder diffraction and TEM electron diffraction measurements suggest these in-plane defects may result from the rupture of Se-Se bonds and the formation of nanorods and nanowires by NbSe2 sheet rolling.
BibTeX: @article{Bartolomé2010, author = {Bartolomé, E. and Bartolomé, J. and Arauzo, A. and Eremenko, V.V. and Sirenko, V.A.}, title = {AC response of 2H-NbSe2 single crystals with electron-irradiation-induced defects}, journal = {Journal of Physics Condensed Matter}, year = {2010}, volume = {22}, number = {29}, pages = {295702}, doi = {http://dx.doi.org/10.1088/0953-8984/22/29/295702} }
Belevtsev B., Dalakova N., Panfilov A., Beliayev E.	Anomalies of conductivity behavior near the paramagnetic-antiferromagnetic transition in single-crystals La2 CuO4 + δ [Abstract] [BibTeX]	2010	Physica B: Condensed Matter Vol. 405(5), pp. 1307-1311	DOI
Abstract: The temperature dependences of resistance, R (T), of two single-crystals La2 CuO4 + δ samples have been studied with the aim to detect a possible change in the R (T) behavior induced by paramagnetic-antiferromagnetic (PM-AFM) transition. One of the samples with δ ≲ 0.01, was fairly homogeneous in oxygen distribution (not phase-separated) with Néel temperature TN ≈ 266 K. Conductivity of this sample has been determined by Mott's variable-range hopping below TN. The other, far less resistive, sample with δ ≈ 0.05, was inhomogeneous (phase-separated) showing both PM-AFM (TN ≈ 205 K) and superconducting (Tc ≈ 25 K) transitions. It is found that for the homogeneous sample the resistivity decreases above TN far faster with temperature than below it (for both directions of measuring current, parallel and perpendicular to basal CuO2 planes). A similar behavior of conductivity near PM-AFM transition is also found for the phase-separated and less resistive sample. In this case a clear kink in R (T) curve near TN ≈ 205 K can be seen. Furthermore, a transition to metallic (dR / dT > 0) behavior occurs far enough above TN. The observed behavior of the samples studied is related to increased delocalization of charge carriers above TN. This is in accordance with decrease in the AFM correlation length and corresponding enhancement of the hole mobility above TN known for low-doped lanthanum cuprates.
BibTeX: @article{Belevtsev20101307, author = {Belevtsev, B.I. and Dalakova, N.V. and Panfilov, A.S. and Beliayev, E.Yu.}, title = {Anomalies of conductivity behavior near the paramagnetic-antiferromagnetic transition in single-crystals La2 CuO4 + δ}, journal = {Physica B: Condensed Matter}, year = {2010}, volume = {405}, number = {5}, pages = {1307-1311}, doi = {http://dx.doi.org/10.1016/j.physb.2009.11.074} }
Beznosov A., Fertman E., Desnenko V., Feher A., Kajnakova M., Loginov A.	Crystal-field and Nd-Mn exchange interaction in Nd2/3Ca 1/3MnO3 [Abstract] [BibTeX]	2010	Journal of Physics: Conference Series Vol. 200(3), pp. 032007	DOI
Abstract: A study of the low field magnetization and specific heat in magnetic fields up to 9 T of Nd2/3Ca1/3MnO3 perovskite in the 2-30 K temperature range has been done. All the specific heat data show broadened Schottky-like anomaly below 20 K. We suppose that such a behavior originates from the Nd magnetic ordering caused by the splitting of the Nd 3+ ions ground-state doublet (GSD) in the effective molecular field Hex of Mn spin system supplemented by an applied external magnetic field. The zero field GSD splitting is an evidence of a strong exchange coupling between Nd and Mn magnetic subsystems. The Nd-ions magnetic ordering introduces an additional contribution to the ferromagnetic moment producing anomalies of the field-cooled and zero-field-cooled magnetizations of the system below 28 K. The broadened Schottky-like anomalies found are fitted for every field by a set of three Schottky functions. Applied magnetic field extends the anomaly region and shifts it to the higher temperatures. Splitting of the higher crystal field Kramers doublets gives an additional contribution to the heat capacity under magnetic fields. The GSD g-factors g\|\| and g⊥ was estimated as 3.4 and 2.2, respectively, and Hex as 9 T.
BibTeX: @article{Beznosov2010, author = {Beznosov, A. and Fertman, E. and Desnenko, V. and Feher, A. and Kajnakova, M. and Loginov, A.}, title = {Crystal-field and Nd-Mn exchange interaction in Nd2/3Ca 1/3MnO3}, journal = {Journal of Physics: Conference Series}, year = {2010}, volume = {200}, number = {3}, pages = {032007}, doi = {http://dx.doi.org/10.1088/1742-6596/200/3/032007} }
Fedorchenko A., Lyakhno V., Shnyrkov V.	SQUID magnetometer for structuroscopy of structural materials [Abstract] [BibTeX]	2010	Problems of Atomic Science and Technology Vol. 65(1), pp. 150-156	URL
Abstract: We present a design of a magnetometer intended for early diagnostics of radiation damages in structural materials. The magnetometer is an rf SQUID material susceptometer based on a helium cryostat shield. The features and characteristics of such magnetometers are analyzed, the upper limit parameters achievable in the used schemes are estimated. The design of main parts, the key parameters optimization methods, the operation and calibration algorithms are described. The interference sources while measuring magnetic properties of the materials in fields B=3...4 T are revealed. The techniques to suppress external electromagnetic noises due to special design of the cryostat shield are offered. Some examples of the meter output signals and the best values of the sensitivity to sample magnetic moment variations, of the sample temperature stability, and of the liquid helium evaporation rate are given.
BibTeX: @article{Fedorchenko2010150, author = {Fedorchenko, A.V. and Lyakhno, V.Y. and Shnyrkov, V.I.}, title = {SQUID magnetometer for structuroscopy of structural materials}, journal = {Problems of Atomic Science and Technology}, year = {2010}, volume = {65}, number = {1}, pages = {150-156}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78149386930&partnerID=40&md5=0af687f0c7ba3cf55e4946de785635d8} }
Fedorchenko A., Grechnev G., Desnenko V., Panfilov A., Volkova O., Vasiliev A.	Magnetic properties and electronic structure of LaFeAsO0.85F0.1 [Abstract] [BibTeX]	2010	Low Temperature Physics Vol. 36(3), pp. 230-235	DOI
Abstract: The magnetic properties of the compound LaFeAsO0.85F0.1 were investigated by measurements of the dc magnetization for different values of the magnetic field H=0.02, 1.0 and 2.0T in the temperature range 4.2-300K. Superconducting behavior was found below 26K, whereas a distinct peculiarity in the low-field dependence of the magnetic susceptibility χ(T) was clearly observed at TM≃135K, which resembles a weak ferromagnetic (FM) response with saturation magnetic moment of about 10-4μB per formula unit at 50K. The transition at TM is presumably not governed by magnetic impurities but rather correlated with the antiferromagnetic (AFM) transition in undoped LaFeAsO at about the same temperature. We suggest that the observed magnetic properties of the LaFeAsO0.85F0.1 sample are due to an interplay of FM and AFM transitions, and are presumably related with an intrinsic feature of a small portion of the undoped LaFeAsO phase inherent in our sample. In order to shed light on the problem of magnetic instability of the LaFeAsO, ab initio DFT calculations of the electronic structure and paramagnetic susceptibility were performed within the local spin density approximation. It is shown that a V-shaped peculiarity in the density of electronic states close to the Fermi level can govern magnetic properties of LaFeAsO with fluorine doping and/or oxygen deficiency.
BibTeX: @article{Fedorchenko2010230, author = {Fedorchenko, A.V. and Grechnev, G.E. and Desnenko, V.A. and Panfilov, A.S. and Volkova, O.S. and Vasiliev, A.N.}, title = {Magnetic properties and electronic structure of LaFeAsO0.85F0.1}, journal = {Low Temperature Physics}, year = {2010}, volume = {36}, number = {3}, pages = {230-235}, doi = {http://dx.doi.org/10.1063/1.3331507} }
Gospodarev I., Eremenko V., Kravchenko K., Sirenko V., Syrkin E., Feodos'ev S.	Vibrational characteristics of niobium diselenide and graphite nanofilms [Abstract] [BibTeX]	2010	Low Temperature Physics Vol. 36(4), pp. 344-350	DOI
Abstract: The phonon spectra of niobium diselenide nanofilms, consisting of several structural elements of this compound, as well as graphite nanofilms starting with bigraphene are analyzed at the microscopic level. The partial contributions of the displacements of atoms along the strong and weak coupling directions (i.e. along and perpendicular to the layers) to the phonon density of states are calculated. The characteristic distinguishing features of the vibrational spectral of these structures are analyzed. The fact that our calculations are practically identical to the data obtained from neutron diffraction, acoustic, and optical experiments confirms that the description of the phonon spectra of the compounds is highly accurate. The temperature dependences of the mean-square shifts for bulk samples and nanofilms along different crystallographic directions, making it possible to evaluate the stability of the graphite and niobium diselenide nanofilms at low temperatures, are calculated for each compound studied.
BibTeX: @article{Gospodarev2010344, author = {Gospodarev, I.A. and Eremenko, V.V. and Kravchenko, K.V. and Sirenko, V.A. and Syrkin, E.S. and Feodos'ev, S.B.}, title = {Vibrational characteristics of niobium diselenide and graphite nanofilms}, journal = {Low Temperature Physics}, year = {2010}, volume = {36}, number = {4}, pages = {344-350}, doi = {http://dx.doi.org/10.1063/1.3423025} }
Grechnev G., Desnenko V., Fedorchenko A., Panfilov A., Kolesnichenko Y., Matzui L., Grybova M., Prylutskyy Y., Ritter U., Scharff P.	Structure and magnetic properties of multi-walled carbon nanotubes modified with iron [Abstract] [BibTeX]	2010	Low Temperature Physics Vol. 36(12), pp. 1086-1090	DOI
Abstract: Magnetic properties of multi-walled carbon nanotubes modified with iron (MWCNT+Fe) are studied in detail in the temperature range 4.2-300K. Carbon encapsulated Fe nanoparticles were produced by chemical vapor deposition. Low-temperature SQUID magnetization measurements are supplemented by structural studies employing thermogravimetric (TG) analysis, transmission electron microscopy (TEM), x-ray diffraction spectroscopy (XRD), and scanning electron microscopy (SEM). The magnetic susceptibility of MWCNT+Fe was also studied above room temperature to provide a complete picture of its magnetic phase transitions.
BibTeX: @article{Grechnev20101086, author = {Grechnev, G.E. and Desnenko, V.A. and Fedorchenko, A.V. and Panfilov, A.S. and Kolesnichenko, Y.A. and Matzui, L.Y. and Grybova, M.I. and Prylutskyy, Y.I. and Ritter, U. and Scharff, P.}, title = {Structure and magnetic properties of multi-walled carbon nanotubes modified with iron}, journal = {Low Temperature Physics}, year = {2010}, volume = {36}, number = {12}, pages = {1086-1090}, doi = {http://dx.doi.org/10.1063/1.3530422} }
Troyanchuk I., Bushinsky M., Karpinsky D., Sirenko V., Sikolenko V., Efimov V.	Structural and magnetic phases of Bi 1-xA xFeO 3- δ (A = Sr, Pb) perovskites [Abstract] [BibTeX]	2010	European Physical Journal B Vol. 73(3), pp. 375-381	DOI
Abstract: The Bi 1-xA xFeO 3- δ (A∈=∈Sr,∈Pb) systems have been studied using the X-ray, neutron powder diffraction and magnetization measurements in a magnetic field up to 14 T. It was found that around x ∼ 0.06 the crystal symmetry changes from a rhombohedral (space group R3c) to pseudo-tetragonal. In the composition range 0.07 ≥ x ≥ 0.14 the phases with different symmetry of the unit cell coexist independent of synthesis conditions. The neutron powder diffraction shows that the iron ions have average oxidation state close to 3+. The magnetic structure for Bi 0.5Sr 0.5FeO 3- δ is found to be G-type antiferromagnetic with magnetic moment of about 3.8 μ B/Fe 3+. The weak ferromagnetic state due to magnetoelectric interactions was revealed in the lightly doped rhombohedrally distorted compositions. No evidence for a spontaneous magnetization was observed for the pseudo-tetragonal phases. These compositions show irreversible nonlinear magnetization vs. field behavior apparently due to small local deviations from the collinearity of the magnetic moments.
BibTeX: @article{Troyanchuk2010375, author = {Troyanchuk, I.O. and Bushinsky, M.V. and Karpinsky, D.V. and Sirenko, V. and Sikolenko, V. and Efimov, V.}, title = {Structural and magnetic phases of Bi 1-xA xFeO 3- δ (A = Sr, Pb) perovskites}, journal = {European Physical Journal B}, year = {2010}, volume = {73}, number = {3}, pages = {375-381}, doi = {http://dx.doi.org/10.1140/epjb/e2010-00004-y} }
Zvyagina G., Zhekov K., Bilych I., Zvyagin A., Bezmaternyhk L., Gudim I.	Low-temperature phase transitions in the rare-earth ferroborate Nd0.75Dy0.25Fe3(BO3) 4 [Abstract] [BibTeX]	2010	Low Temperature Physics Vol. 36(3), pp. 279-281	DOI
Abstract: The low-temperature behavior of the elastic characteristics of a Nd0.75Dy0.25Fe3(BO3) 4 single crystal has been studied. Features are found in the temperature and magnetic-field dependences of the velocity and absorption of transverse sound. These features are interpreted as being a manifestation of magnetic phase transitions in the compound studied. The H-T phase diagram is constructed.
BibTeX: @article{Zvyagina2010279, author = {Zvyagina, G.A. and Zhekov, K.R. and Bilych, I.V. and Zvyagin, A.A. and Bezmaternyhk, L.N. and Gudim, I.A.}, title = {Low-temperature phase transitions in the rare-earth ferroborate Nd0.75Dy0.25Fe3(BO3) 4}, journal = {Low Temperature Physics}, year = {2010}, volume = {36}, number = {3}, pages = {279-281}, doi = {http://dx.doi.org/10.1063/1.3331632} }
Zvyagina G., Zhekov K., Bilych I., Zvyagin A., Bezmaternykh L., Gudim I.	Low-temperature behavior of the magnetoelastic characteristics of praseodymium ferroborate [Abstract] [BibTeX]	2010	Low Temperature Physics Vol. 36(4), pp. 296-302	DOI
Abstract: The behavior of the elastic moduli and sound absorption in a PrFe3(B03)4 single crystal at low temperatures is studied. A transition of the magnetic infsystem into an antiferromagnetically ordered state is manifested in the temperature behavior of the sound velocities and absorption. The characteristic behavior of the elastic properties of PrFe3(B03)4 in an external magnetic field is observed. A phenomenological theory that gives a qualitative description of the observed features is constructed. It is proposed that a weak magnetic moment exists in the crystal.
BibTeX: @article{Zvyagina2010296, author = {Zvyagina, G.A. and Zhekov, K.R. and Bilych, I.V. and Zvyagin, A.A. and Bezmaternykh, L.N. and Gudim, I.A.}, title = {Low-temperature behavior of the magnetoelastic characteristics of praseodymium ferroborate}, journal = {Low Temperature Physics}, year = {2010}, volume = {36}, number = {4}, pages = {296-302}, doi = {http://dx.doi.org/10.1063/1.3420962} }
Grechnev G.E., Desnenko V.A., Fedorchenko A.V., Panfilov A.S., Gnatchenko S.L., Zhuravleva I.P., Volkova O.S., Vasiliev A.N., Tsurkan V.V.	Pressure effect on electronic structure and magnetic properties of iron-based high Tc superconductors [Abstract] [BibTeX]	2010	High Pressure Physics and Technics Vol. 20(4), pp. 60-69	URL
Abstract: Pressure effects on electronic structure and magnetic properties of iron-based superconductors FeSe1-xTex (x ~ 0, 0.5 and 1.0) and LaFeAsO are investigated. The superconducting transition was observed at TC ~ 8, 13.6-14.2, and 26 K in FeSe0.963, FeSe0.5Te0.5, and LaFeAsO0.85F0.1, respectively. The intrinsic magnetic susceptibility χ in the series of FeSe0.963, FeSe0.5Te0.5 and FeTe is found to increase gradually approximately 10 times as much with Te content. A kink in the low-field dependence of χ(T) was detected at TM ~ 135 K for LaFeAsO0.85F0.1. The electronic structures and paramagnetic susceptibilities of the studied compounds are calculated ab initio in external magnetic field as a function of atomic volume and structural parameter Z, which specifies the relative height of chalcogen atoms above iron plane. The calculated field-induced magnetic moments and their volume derivatives indicate that these systems are in a close proximity to a quantum critical point. For FeSe and FeTe the calculated paramagnetic susceptibilities reveal a large magnetovolume effect and a drastic sensitivity to parameter Z.
BibTeX: @article{grechnev2010ii, author = {Grechnev, G. E. and Desnenko, V. A. and Fedorchenko, A. V. and Panfilov, A. S. and Gnatchenko, S. L. and Zhuravleva, I. P. and Volkova, O. S. and Vasiliev, A. N. and Tsurkan, V. V.}, title = {Pressure effect on electronic structure and magnetic properties of iron-based high Tc superconductors}, journal = {High Pressure Physics and Technics}, year = {2010}, volume = {20}, number = {4}, pages = {60-69}, url = {http://www.fti.dn.ua/site/wp-content/uploads/2014/02/2010_4_6.pdf} }
Avramenko Y., Bezuglyǐ E., Burma N., Fil V.	Electron sound in metals [Abstract] [BibTeX]	2009	Low Temperature Physics Vol. 35(8), pp. 724-734	DOI
Abstract: This work is devoted to the investigation of electron sound-oscillations coupled with elastic deformation of the electron distribution function and propagating with the Fermi velocity. The amplitude-phase relations characterizing the behavior of electron sound in Ga single crystals are determined experimentally. A model problem of excitation of electron sound in a compensated metal with equivalent bands is solved for a finite sample with diffuse scattering of electrons at the interfaces. It is determined that the displacement amplitude of the receiving interface is two orders of magnitude greater than the elastic amplitude characteristic for the wave due to electron pressure. It is established that the changes occurring in the amplitude and phase of the electron sound waves at a superconducting transition do not depend on the path traversed by the wave, i.e. they refer only to the behavior of the conversion coefficient.
BibTeX: @article{Avramenko2009724, author = {Avramenko, Yu.A. and Bezuglyǐ, E.V. and Burma, N.G. and Fil, V.D.}, title = {Electron sound in metals}, journal = {Low Temperature Physics}, year = {2009}, volume = {35}, number = {8}, pages = {724-734}, doi = {http://dx.doi.org/10.1063/1.3224732} }
Baranovskiy A., Grechnev G., Shitsevalova N., Sluchanko D., Glushkov V., Demishev S., Sluchanko N.	Hall effect and magnetic ordering in RB12 [Abstract] [BibTeX]	2009	Low Temperature Physics Vol. 35(7), pp. 565-567	DOI
Abstract: The concentration of carriers in Lu B12 is evaluated theoretically by applying ab initio FP-LMTO calculations. Theoretical results are found to be in agreement with high-precision measurements of the Hall coefficient RH (T) carried out on single crystals of the rare-earth dodecaborides RB12 (R=Ho,Er,Tm,Lu) at temperatures 1.8-300 K. The nature of the antiferromagnetic ordering in RB12 is investigated within an RKKY-like model supplemented by comprehensive electronic structure calculations for paramagnetic, ferromagnetic, and antiferromagnetic phases.
BibTeX: @article{Baranovskiy2009565, author = {Baranovskiy, A.E. and Grechnev, G.E. and Shitsevalova, N.Y. and Sluchanko, D.N. and Glushkov, V.V. and Demishev, S.V. and Sluchanko, N.E.}, title = {Hall effect and magnetic ordering in RB12}, journal = {Low Temperature Physics}, year = {2009}, volume = {35}, number = {7}, pages = {565-567}, doi = {http://dx.doi.org/10.1063/1.3170932} }
Bartolomé J., Bartolomé E., Eremenko V., Ibulaev V., Sirenko V., Petrusenko Y.	Magnetic anisotropy in 2H-NbSe2 electron irradiated single crystals [Abstract] [BibTeX]	2009	Solid State Phenomena Vol. 152-153, pp. 470-473	DOI
Abstract: The anisotropic magnetic properties of the metallic layered compound with hexagonal crystal structure 2H-NbSe2 are investigated as a function of their dependence on high-energy electron irradiation. Pauli paramagnetism of free electrons is shown to dominate the magnetic susceptibility, χp. The anisotropy is related to spin-orbit effects on the hybridized electronic states. Irradiation affects the density of states at the Fermi surface, increasing both χp and the anisotropy. Below a threshold temperature, Ts=54 K, the paramagnetic contribution, which increases with the dose, is ascribed to dangling bonds, nanotubes and nanorods generated by irradiation.
BibTeX: @article{Bartolomé2009470, author = {Bartolomé, J. and Bartolomé, E. and Eremenko, V.V. and Ibulaev, V.V. and Sirenko, V.A. and Petrusenko, Yu.T.}, title = {Magnetic anisotropy in 2H-NbSe2 electron irradiated single crystals}, journal = {Solid State Phenomena}, publisher = {Trans Tech Publications Ltd}, year = {2009}, volume = {152-153}, pages = {470-473}, doi = {http://dx.doi.org/10.4028/www.scientific.net/SSP.152-153.470} }
Beznosov A., Fertman E., Desnenko V., Feher A., Kajaková M., Ritter C., Khalyavin D.	Low-temperature phase segregation in La2/3 Ba1/3 Mn O3: Manifestation of nonequilibrium thermodynamics [Abstract] [BibTeX]	2009	Low Temperature Physics Vol. 35(6), pp. 449-454	DOI
Abstract: Thermodynamic characteristics of the perovskite-like compound La2/3 Ba1/3 Mn O3, exhibiting a structural phase transformation of the martensitic type with a characteristic temperature Ts ≈200 K, are studied in the temperature range 2-340 K. Step-like hysteretic temperature behavior of the effective heat capacity is revealed at 150-250 K and attributed to the discrete kinetics and a latent heat of the martensitic transformation. The magnetic subsystem is found to exhibit a magnetic glass state below 220 K and temperature hysteresis of the magnetic susceptibility clearly pronounced in the 40-100 K and 180-230 K regions. The Debye and Einstein temperatures, θD =230 K and θE =500 K, respectively, derived from the experimental Debye-Waller factors for the La/Ba, Mn, and O sublattices, are used to refine contributions from the structural and magnetic transformations to the heat capacity and to reveal thermodynamically nonequilibrium states.
BibTeX: @article{Beznosov2009449, author = {Beznosov, A.B. and Fertman, E.L. and Desnenko, V.A. and Feher, A. and Kajaková, M. and Ritter, C. and Khalyavin, D.}, title = {Low-temperature phase segregation in La2/3 Ba1/3 Mn O3: Manifestation of nonequilibrium thermodynamics}, journal = {Low Temperature Physics}, year = {2009}, volume = {35}, number = {6}, pages = {449-454}, doi = {http://dx.doi.org/10.1063/1.3151991} }
Eremenko V., Sirenko V., Ibulaev V., Shvedun M., Andre G.	X-ray scattering on charge-density-wave superconductor 2H-NbSe2 [Abstract] [BibTeX]	2009	Journal of Physics: Conference Series Vol. 150(4), pp. 042029	DOI
Abstract: A direct evidence of X-ray scattering by electron modulation in a charge-density wave metal dominating over the periodic lattice distortion (PLD) is presented for hexagonal modification of niobium diselenide (2H-NbSe 2). Namely, new pronounced features appear in X-ray diffraction below TCDW indexed in the space group D3h 1 with a doubled in-plane parameter a and the inversion symmetry axis instead of screw one. Above TCDW transition, the space group D6h 4 with lattice parameters a0=3.44, c=12.8 is revealed in agreement with published data. The observed difference is due in particular to different mechanisms of neutron and X-rays scattering by spatial distribution of nuclei or electron density, respectively. A CDW formation in 2H-NbSe 2 is then accompanied by spatial modulation of electron density with periodicity 2a, manifested in X-ray scattering with a nuclei shift insufficient for neutron scattering. Indeed, numerous studies show enigmatic absence of Fermi-surface nesting in 2H-NbSe2 and, eventually, long coherence length. Within McMillan's consideration it means that in this case, electron modulation should dominate the distortion of periodic crystal potential rather than commonly observed periodic lattice distortion, e.g. in TaSe2.
BibTeX: @article{Eremenko2009, author = {Eremenko, V. and Sirenko, V. and Ibulaev, V. and Shvedun, M. and Andre, G.}, title = {X-ray scattering on charge-density-wave superconductor 2H-NbSe2}, journal = {Journal of Physics: Conference Series}, year = {2009}, volume = {150}, number = {4}, pages = {042029}, doi = {http://dx.doi.org/10.1088/1742-6596/150/4/042029} }
Eremenko V., Ibulaev V., Sirenko V., Shvedun M.	On the character of the scattering of wide-band x-ray radiation in the low-temperature phase of 2H-Nb Se2 [Abstract] [BibTeX]	2009	Low Temperature Physics Vol. 35(2), pp. 166-168	DOI
Abstract: The intensity of x-ray scattering in the layered metal 2H-Nb Se2 has been investigated experimentally in the temperature range below the temperature of the transition into the charge-density wave state. It is shown that the relation I∼ (TC -T)-γ with TC ∼30 K and γ=1.6±0.2, as is characteristic for quasi-elastic (quasi-Bragg) scattering, describes the scattering intensity. Such scattering is strong when the width Δ εXR of the spectral distribution of the x-ray radiation is greater than the spectral width of the fluctuations Δ εf of the order parameter. The inequality Δ εf <Δ εf holds for scattering of slow neutrons, for which quasi-elastic scattering is immeasurably weak.
BibTeX: @article{Eremenko2009166, author = {Eremenko, V.V. and Ibulaev, V.V. and Sirenko, V.A. and Shvedun, M.Yu.}, title = {On the character of the scattering of wide-band x-ray radiation in the low-temperature phase of 2H-Nb Se2}, journal = {Low Temperature Physics}, year = {2009}, volume = {35}, number = {2}, pages = {166-168}, doi = {http://dx.doi.org/10.1063/1.3075950} }
Eremenko V., Sirenko V., Ibulaev V., Bartolomé J., Arauzo A., Reményi G.	Heat capacity, thermal expansion and pressure derivative of critical temperature at the superconducting and charge density wave (CDW) transitions in NbSe2 [Abstract] [BibTeX]	2009	Physica C: Superconductivity and its Applications Vol. 469(7-8), pp. 259-264	DOI
Abstract: The results of the study of thermodynamic properties of the anisotropic 2H-NbSe2 compound, in the superconducting to normal state (SN) upper critical field HC2-TC transition line, and in the charge density wave (CDW) transition are presented. Isothermal heat capacity and magnetization measurements were performed to determine the heat capacity jump at the HC2-TC transition line. With these results the validity of the Second Ehrenfest relation for this type II superconductor was checked. The temperature dependences of the heat capacity and the thermal expansion along the crystallographic axis scyrillic were measured. Both properties manifest the sharp features of BCS-type at the superconducting transition and more diffuse features at the CDW transitions. These results, together with the First Ehrenfest relation, allowed us to estimate the critical temperature derivative on uniaxial pressure applied along the hexagonal axis scyrillic, pIIscyrillic, (∂ TSN / ∂ p/ / c)P → 0 = + 1.45 ± 0.05 K / GPa. The same methodology has been applied to the CDW transition, where a positive derivative on uniaxial pressure was deduced.
BibTeX: @article{Eremenko2009259, author = {Eremenko, V. and Sirenko, V. and Ibulaev, V. and Bartolomé, J. and Arauzo, A. and Reményi, G.}, title = {Heat capacity, thermal expansion and pressure derivative of critical temperature at the superconducting and charge density wave (CDW) transitions in NbSe2}, journal = {Physica C: Superconductivity and its Applications}, year = {2009}, volume = {469}, number = {7-8}, pages = {259-264}, doi = {http://dx.doi.org/10.1016/j.physc.2009.02.015} }
Eremenko V., Ibulaev V., Sirenko V., Shvedun M., Kulikov L., Petrusenko Y., Borisenko V., Astakhov A., Barankov D.	Electron doping of Nb Se2 [Abstract] [BibTeX]	2009	Low Temperature Physics Vol. 35(5), pp. 430-433	DOI
Abstract: The influence of fast-electron irradiation on the properties of the hexagonal modification of niobium diselenide, 2H-Nb Se2, is investigated by the methods of x-ray and electron diffractometry. The observed changes in the diffractograms are explained by a redistribution of the electron density under irradiation, viz., an increase of the electron density in the planes with high packing density-the basal and prismatic planes 110, 210. The appearance of diffuse scattering of x rays and electrons at high doses of irradiation is attributed to growth of the electron density of the Fermi liquid.
BibTeX: @article{Eremenko2009430, author = {Eremenko, V.V. and Ibulaev, V.V. and Sirenko, V.A. and Shvedun, M.Yu. and Kulikov, L.M. and Petrusenko, Yu.T. and Borisenko, V.M. and Astakhov, A.N. and Barankov, D.Yu.}, title = {Electron doping of Nb Se2}, journal = {Low Temperature Physics}, year = {2009}, volume = {35}, number = {5}, pages = {430-433}, doi = {http://dx.doi.org/10.1063/1.3132767} }
Fedorchenko A., Grechnev G., Panfilov A., Logosha A., Svechkarev I., Filippov V., Lyashchenko A., Evdokimova A.	Anisotropy of the magnetic properties and the electronic structure of transition-metal diborides [Abstract] [BibTeX]	2009	Low Temperature Physics Vol. 35(11), pp. 862-868	DOI
Abstract: The temperature dependences of the magnetic susceptibility and its anisotropy ΔX=X- ⊥ have been measured for hexagonal single crystals of transition-metal diborides M B2 (M=Sc,Ti,V,Zr,Hf) in the temperature interval 4.2-300 K. It is found that the anisotropy ΔX is weakly temperature-dependent, a nonmonotonic function of the filling of the hybridized p-d conduction band, and largest for group-IV transition metals. First-principles calculations of the electronic structure of diborides and the values of the paramagnetic contributions (spin and Van Vleck) to their susceptibility show that the behavior of the magnetic anisotropy is due to the competition between Van Vleck paramagnetism and orbital diamagnetism of the conduction electrons.
BibTeX: @article{Fedorchenko2009862, author = {Fedorchenko, A.V. and Grechnev, G.E. and Panfilov, A.S. and Logosha, A.V. and Svechkarev, I.V. and Filippov, V.B. and Lyashchenko, A.B. and Evdokimova, A.V.}, title = {Anisotropy of the magnetic properties and the electronic structure of transition-metal diborides}, journal = {Low Temperature Physics}, year = {2009}, volume = {35}, number = {11}, pages = {862-868}, doi = {http://dx.doi.org/10.1063/1.3266916} }
Fertman E., Beznosov A., Desnenko V., Kajnakova M., Feher A.	Low temperature heat capacity of Nd2/3Ca1/3MnO 3 and (Nd0.9 Y0.1)2/3Ca1/3MnO 3 manganites: Transformation of the Schottky-like anomaly [Abstract] [BibTeX]	2009	Journal of Physics: Conference Series Vol. 150(4), pp. 042031	DOI
Abstract: Effect of Y-doping on interactions in the spin system of the colossal magnetoresistance compound Nd2/3Ca1/3MnO3 has been studied by the thermal relaxation heat capacity and neutron diffraction techniques in the 2 - 30 K temperature range. In 5 K temperature region a broadened Schottky-like specific heat anomaly Csch(T) has been foDnd both in the parent Nd2/3Ca1/3MnO3 and in the doped (Nd0.9Y0.1)2/3Ca1/3MnO 3 compounds. The experimental data were successfully fitted by a set of three two-level Schottky contributions, implying a broadening of the exited level in the system with randomly distributed Y ions. Replacement of 10 % Nd ions by nonmagnetic Y ions leads to the about 10 % enlargement of the splitting of the ground state doublet of Nd3+ ion.
BibTeX: @article{Fertman2009, author = {Fertman, E. and Beznosov, A. and Desnenko, V. and Kajnakova, M. and Feher, A.}, title = {Low temperature heat capacity of Nd2/3Ca1/3MnO 3 and (Nd0.9 Y0.1)2/3Ca1/3MnO 3 manganites: Transformation of the Schottky-like anomaly}, journal = {Journal of Physics: Conference Series}, year = {2009}, volume = {150}, number = {4}, pages = {042031}, doi = {http://dx.doi.org/10.1088/1742-6596/150/4/042031} }
Fertman E., Beznosov A., Desnenko V., Kajnakova M., Feher A.	Phase transformations in Nd2/3Ca1/3MnO3: Effect of y substitution [Abstract] [BibTeX]	2009	Solid State Phenomena Vol. 152-153, pp. 108-111	DOI
Abstract: It was found that below the room temperature both parent Nd 2/3Ca1/3MnO3 and doped (Nd0.9Y 0.1)2/3Ca1/3MnO3 compounds exhibit a sequence of phase transformations: charge ordering, structural transformation of 0-0 type within the orthorhombic structure, and three magnetic transitions. Three different types of long-range magnetic order co-exist in (Nd 0.9Y0.1)2/3Ca1/3MnO3 at low temperatures (as it was earlier found in Nd2/3Ca 1/3MnO3): the antiferromagnetic orderings of PCE and DE types existing below ∼110 K and ∼60 K, respectively, and the ferromagnetic one of B type existing below ∼42 K. Charge ordering occurs at 290 K in the doped compound. Diluting of Nd subsystem by Y in the parent perovskite has opposite effects on the temperatures of magnetic and charge orderings: the temperatures of all magnetic transformations are reduced in the doped compound by 20-30 K, while the charge ordering one increases by ∼80 K. A relationship between evolution of the phase transformation temperatures and crystal and electronic structures of the compound are analyzed.
BibTeX: @article{Fertman2009108, author = {Fertman, E. and Beznosov, A. and Desnenko, V. and Kajnakova, M. and Feher, A.}, title = {Phase transformations in Nd2/3Ca1/3MnO3: Effect of y substitution}, journal = {Solid State Phenomena}, publisher = {Trans Tech Publications Ltd}, year = {2009}, volume = {152-153}, pages = {108-111}, doi = {http://dx.doi.org/10.4028/www.scientific.net/SSP.152-153.108} }
Fertman E., Beznosov A., Sheptyakov D., Desnenko V., Kajnakova M., Feher A., Khalyavin D.	Effect of Y-doping on the magnetic and charge orderings in Nd2/3Ca1/3MnO3 [Abstract] [BibTeX]	2009	Journal of Magnetism and Magnetic Materials Vol. 321(4), pp. 316-320	DOI
Abstract: The shifts of the magnetic and charge ordering transition temperatures caused by Nd substitution for Y in Nd2/3Ca1/3MnO3 CMR narrow-band perovskite manganite have been studied. At low temperatures, three different long-range magnetic orderings consistent with a phase separation scenario have been observed in the doped compound (Nd0.9Y0.1)2/3Ca1/3MnO3 by neutron-diffraction study: the antiferromagnetic orderings of PCE and DE types existing below ∼110 and ∼60 K, respectively, and the ferromagnetic one of B type existing below ∼42. Magnetic phase transformations temperatures as well as those of charge ordering have been found to be structural-dependent. Y-doping leads to the decrease of the anisotropy of the orthorhombic Pnma crystal lattice b/√2c, which causes a decrease of the indirect exchange parameters in the system and thus a decrease in the magnetic transformation temperatures for 20-30 K in the doped compound. Doping leads as well to the higher level of the coherent Jahn-Teller distortions of the MnO6 octahedra in the 200-300 K temperature region, which results in the increase of the charge ordering temperature for ∼80 K.
BibTeX: @article{Fertman2009316, author = {Fertman, E. and Beznosov, A. and Sheptyakov, D. and Desnenko, V. and Kajnakova, M. and Feher, A. and Khalyavin, D.}, title = {Effect of Y-doping on the magnetic and charge orderings in Nd2/3Ca1/3MnO3}, journal = {Journal of Magnetism and Magnetic Materials}, year = {2009}, volume = {321}, number = {4}, pages = {316-320}, doi = {http://dx.doi.org/10.1016/j.jmmm.2008.09.006} }
Galetich I., Gospodarev I., Grishaev V., Eremenko A., Kravchenko K., Sirenko V., Feodosyev S.	Vibrational characteristics of the niobium dichalcogenide. Bulk samples and nanofilms [Abstract] [BibTeX]	2009	Superlattices and Microstructures Vol. 45(6), pp. 564-575	DOI
Abstract: A model of the niobium diselenide crystal lattice has been proposed. This model sufficiently describes the vibrational characteristics of both bulk samples and nanofilms with a thickness beyond one three-layered structural element. Calculation of the local Green functions and mean-squared atom amplitudes have been performed using the Jacobi-matrix method. Phonon density of states features stipulated by acoustic branches and low-frequency low-dispersion optical modes cross-over have been analyzed.
BibTeX: @article{Galetich2009564, author = {Galetich, I.K. and Gospodarev, I.A. and Grishaev, V.I. and Eremenko, A.V. and Kravchenko, K.V. and Sirenko, V.A. and Feodosyev, S.B.}, title = {Vibrational characteristics of the niobium dichalcogenide. Bulk samples and nanofilms}, journal = {Superlattices and Microstructures}, year = {2009}, volume = {45}, number = {6}, pages = {564-575}, doi = {http://dx.doi.org/10.1016/j.spmi.2009.03.008} }
Ghoshray K., Pahari B., Ghoshray A., Eremenko V., Sirenko V., Suits B.	93Nb NMR study of the charge density wave state in NbSe 2 [Abstract] [BibTeX]	2009	Journal of Physics Condensed Matter Vol. 21(15), pp. 155701	DOI
Abstract: 93Nb NMR studies were carried out for a single crystal of NbSe2 at 73.328MHz in the temperature range 9-300K to investigate the normal and charge density wave (CDW) states. Detailed analysis of the NMR line shape of the central transition using a classical incommensurate model reveals the change in the conduction electron spin dynamics from above TCDW. An increase of the Knight shift below TCDW reflects modification to the uniform part of the conduction electron density of states. As suggested theoretically, the Knight shift distribution is found to be directly proportional to the square of the amplitude of the CDW. The results further indicate an incommensurate CDW state in 2H-NbSe2. Analysis of the NMR spectra using the McMillan incommensurate model suggests a large value of the discommensuration parameter (γ) which is almost temperature independent, in contrast to the much smaller value previously reported in the case of 2H-TaSe2.
BibTeX: @article{Ghoshray2009, author = {Ghoshray, K. and Pahari, B. and Ghoshray, A. and Eremenko, V.V. and Sirenko, V.A. and Suits, B.H.}, title = {93Nb NMR study of the charge density wave state in NbSe 2}, journal = {Journal of Physics Condensed Matter}, year = {2009}, volume = {21}, number = {15}, pages = {155701}, doi = {http://dx.doi.org/10.1088/0953-8984/21/15/155701} }
Grechnev G., Panfilov A., Fedorchenko A., Filippov V., Lyashchenko A., Vasiliev A.	Effect of pressure on the magnetic properties of Cr B2 [Abstract] [BibTeX]	2009	Low Temperature Physics Vol. 35(7), pp. 531-535	DOI
Abstract: The magnetic susceptibility χ of the itinerant antiferromagnet Cr B2 with TN ≃87 K is studied as a function of the hydrostatic pressure up to 2 kbar at fixed temperatures 78 and 300 K. The pressure effect χ on is found to be negative in sign and weakly dependent on the magnetic state of the compound. In addition, the measured pressure dependence of the Ńel temperature, dTN /dP=0. 1±0.1 K/kbar, is roughly two orders of magnitude smaller than the corresponding value for the pure chromium. The main contributions to χ and their volume dependence are calculated ab initio within the local spin density approximation, and they turn out to be in close agreement with the experimental data.
BibTeX: @article{Grechnev2009531, author = {Grechnev, G.E. and Panfilov, A.S. and Fedorchenko, A.V. and Filippov, V.B. and Lyashchenko, A.B. and Vasiliev, A.N.}, title = {Effect of pressure on the magnetic properties of Cr B2}, journal = {Low Temperature Physics}, year = {2009}, volume = {35}, number = {7}, pages = {531-535}, doi = {http://dx.doi.org/10.1063/1.3168639} }
Grechnev G.	Magnetic-field-induced effects in the electronic structure of itinerant d - And f -metal systems [Abstract] [BibTeX]	2009	Low Temperature Physics Vol. 35(8), pp. 638-651	DOI
Abstract: A paramagnetic response of transition metals and itinerant d - and f -metal compounds in an external magnetic field is studied by employing ab initio full-potential LMTO method in the framework of the local spin density approximation. Within this method the anisotropy of the magnetic susceptibility in hexagonal close-packed transition metals is evaluated for the first time. This anisotropy is owing to the orbital Van Vleck-like paramagnetic susceptibility, which is revealed to be substantial in transition-metal systems due to hybridization effects in the electronic structure. It is demonstrated that compounds TiCo, Ni3 Al, Y Co2, Ce Co2, Y Ni5, La Ni5, and Ce Ni5 are strong paramagnets close to the quantum critical point. For these systems the Stoner approximation underestimates the spin susceptibility, whereas the calculated field-induced spin moments provide a good description of the large paramagnetic susceptibilities and magnetovolume effects. It is revealed that an itinerant description of hybridized f electrons produces magnetic properties of the compounds Ce Co2, Ce Ni5, U Al3, U Ga 3, U Si3, and U Ge3 in close agreement with experiment. In the uranium compounds U X3 the strong spin-orbit coupling together with hybridization effects give rise to peculiar magnetic states in which the field-induced spin moments are antiparallel to the external field, and the magnetic response is dominated by the orbital contribution.
BibTeX: @article{Grechnev2009638, author = {Grechnev, G.E.}, title = {Magnetic-field-induced effects in the electronic structure of itinerant d - And f -metal systems}, journal = {Low Temperature Physics}, year = {2009}, volume = {35}, number = {8}, pages = {638-651}, doi = {http://dx.doi.org/10.1063/1.3224723} }
Grechnev G., Fedorchenko A., Logosha A., Panfilov A., Svechkarev I., Filippov V., Lyashchenko A., Evdokimova A.	Electronic structure and magnetic properties of transition metal diborides [Abstract] [BibTeX]	2009	Journal of Alloys and Compounds Vol. 481(1-2), pp. 75-80	DOI
Abstract: The temperature dependencies of the magnetic susceptibility χ and its anisotropy Δ χ = χnorm of matrix - χ⊥ were measured for the hexagonal single crystalline TB2 compounds (T = Sc, Ti, Zr, Hf, V and Cr) in the temperature range 4.2-300 K. It was found that Δ χ varies strongly and nonmonotonously with the filling of the hybridized d-band, being almost temperature independent and the largest for the diborides of group 4 metals. Ab initio calculations of the electronic structure and susceptibility of the diborides provide evidence that magnetic anisotropy originates from competing Van Vleck paramagnetism and the orbital diamagnetism of conduction electrons.
BibTeX: @article{Grechnev200975, author = {Grechnev, G.E. and Fedorchenko, A.V. and Logosha, A.V. and Panfilov, A.S. and Svechkarev, I.V. and Filippov, V.B. and Lyashchenko, A.B. and Evdokimova, A.V.}, title = {Electronic structure and magnetic properties of transition metal diborides}, journal = {Journal of Alloys and Compounds}, year = {2009}, volume = {481}, number = {1-2}, pages = {75-80}, doi = {http://dx.doi.org/10.1016/j.jallcom.2009.03.123} }
Lyakhno V., Fedorchenko A., Kivirenko O., Shnyrkov V.	FRP Dewar for measurements in high pulsed magnetic fields [Abstract] [BibTeX]	2009	Cryogenics Vol. 49(8), pp. 425-428	DOI
Abstract: We describe a liquid helium glass-fibre reinforced plastic (G-FRP) Dewar which we designed, fabricated and tested for excitation spectrum measurements in high pulsed magnetic fields of up to 50 T. The sensitivity of high-resolution magnetic measurements carried out at low temperatures in such high fields is limited inevitably by magnetic and electric properties of the structural Dewar materials involved. Magnetic properties of various G-FRP Dewar-purpose materials are explored with a χ-meter furnished with a RF SQUID magnetometer. The Dewar materials and multilayer insulation effects contributing to the magnetic response signal are analyzed. It has also been discovered that field noise caused by the magnetization of the Dewar materials can be suppressed substantially by using special glass-epoxy technologies. The liquid helium evaporation rate is 3.8 l/day while the hold time is 27 h, the influencing factors are discussed.
BibTeX: @article{Lyakhno2009425, author = {Lyakhno, V.Yu. and Fedorchenko, A.V. and Kivirenko, O.B. and Shnyrkov, V.I.}, title = {FRP Dewar for measurements in high pulsed magnetic fields}, journal = {Cryogenics}, year = {2009}, volume = {49}, number = {8}, pages = {425-428}, doi = {http://dx.doi.org/10.1016/j.cryogenics.2009.06.004} }
Peschanskii A., Gnezdilov V., Fomin V., Eremenko V., Lemmens P., Choi K.-Y., Berger H.	Raman scattering study of a two-dimensional S = 1 quantum spin system Ni5(TeO3)4Cl2 [Abstract] [BibTeX]	2009	Ukrainian Journal of Physics Vol. 54(1-2), pp. 196-201	URL
Abstract: The transition metal tellurium oxychloride, Ni5(TeO3)4Cl2, has been investigated by the Raman scattering method at temperatures of 15-300 K. Sixty two phonon modes (of the total 69 Raman-active phonon modes allowed for the monoclinic C6 2h structure) are identified in the spectra, and their behavior is analyzed. Several distinct features are observed in Raman spectra at low temperatures: (i) three low-frequency bands (22.3, 29.4, and 49.0 cm-1 at T = 15 K) with a temperature behavior characteristic of the one-magnon scattering and (ii) a band at 56.3 cm-1 with a pronounced temperature dependence. The origin ofthe low-temperature bands is discussed.
BibTeX: @article{Peschanskii2009196, author = {Peschanskii, A.V. and Gnezdilov, V.P. and Fomin, V.I. and Eremenko, V.V. and Lemmens, P. and Choi, K.-Y. and Berger, H.}, title = {Raman scattering study of a two-dimensional S = 1 quantum spin system Ni5(TeO3)4Cl2}, journal = {Ukrainian Journal of Physics}, publisher = {National Academy of Sciences of Ukraine}, year = {2009}, volume = {54}, number = {1-2}, pages = {196-201}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78149442672&partnerID=40&md5=ddd00f7a15ab22c114f1f746c58ca12b} }
Sirenko V., Ibulaev V., Shvedun M., Eremenko V.	Wide band XRD study of 2H-NbSe2 in a CDW-regime [Abstract] [BibTeX]	2009	Journal of Physics: Conference Series Vol. 150(4), pp. 042186	DOI
Abstract: Albeit rather simple structure and ample experimental study of charge density wave (CDW) superconductor 2H-NbSe2 its behaviour in a CDW regime (TCDW 32.5 K, TSN 7.2 K) remains unclear. The relevance of the known mechanisms of CDW formation to this hexagonal modification of the niobium diselenide is not straightforward. Occurrence of the lock-in transition in this compound is still debated despite numerous structural investigations by means of diverse diffraction techniques. Here, we present Debye patterns measured in a detail at temperatures 8-35 K with different sources of X-ray irradiation and energy resolution of about 1eV. New features observed in the temperature range 15-30 K are discussed in terms of fluctuation-mediated phase transition.
BibTeX: @article{Sirenko2009, author = {Sirenko, V. and Ibulaev, V. and Shvedun, M. and Eremenko, V.}, title = {Wide band XRD study of 2H-NbSe2 in a CDW-regime}, journal = {Journal of Physics: Conference Series}, year = {2009}, volume = {150}, number = {4}, pages = {042186}, doi = {http://dx.doi.org/10.1088/1742-6596/150/4/042186} }
Sirenko V., Gasparini A., De Visser A., Eremenko V., Ibulaev V., Bruk V.	New details of the Fermi surface of 2H-NbSe2 revealed by quantum oscillations in the magnetostriction [Abstract] [BibTeX]	2009	Journal of Physics: Conference Series Vol. 150(4), pp. 042185	DOI
Abstract: The layered charge-density wave (CDW) superconductor 2H-NbSe2 (TS=7.2 K) is the very first material in which quantum oscillations have been observed in the mixed state by means of magnetization and magnetostriction measurements. The magnetostriction technique offers the advantage that quantum oscillations are particularly pronounced, which is due to pressure sensitivity of the relevant cross-section of the Fermi surface. Moreover, measurements can be performed for a field oriented along the crystallographic axis in contrast to the torque technique that is routinely used. Here we present magnetostriction measurement on a high-quality single-crystalline sample for temperatures 0.25-8.0 K using a sensitive capacitance dilatometer. Two oscillation frequencies are observed at the lowest temperatures for the in-plane orientation of the applied magnetic field. These new data reveal that the Fermi-surface sheet in the first Brillouin zone has two cross-sections, rather than the conventional pan-cake shape.
BibTeX: @article{Sirenko2009a, author = {Sirenko, V. and Gasparini, A. and De Visser, A. and Eremenko, V. and Ibulaev, V. and Bruk, V.}, title = {New details of the Fermi surface of 2H-NbSe2 revealed by quantum oscillations in the magnetostriction}, journal = {Journal of Physics: Conference Series}, year = {2009}, volume = {150}, number = {4}, pages = {042185}, doi = {http://dx.doi.org/10.1088/1742-6596/150/4/042185} }
Azhazha V., Desnenko V., Ozhigov L., Azhazha Z., Svechkaryov I., Fedorchenko A.	The use of magnetic methods for investigating the structure evolution in austenitic stainless steels after a long-term service at nuclear power plant units [Abstract] [BibTeX]	2009	Problems of Atomic Science and Technology Vol. 62(4), pp. 241-246	URL
Abstract: Investigation of the influence on magnetic properties of metals after lengthy operation in power generating units of NPS is carried out by SQUID magnetometer for austenitic steels. The obtained results testify to the high sensitivity of magnetic method on analysis of structure state of materials and point to the prospects of its use for diagnostics of low-magnetic steels.
BibTeX: @article{azhazha2009, author = {Azhazha, V.M. and Desnenko, V.A. and Ozhigov, L.S. and Azhazha, Zh.S. and Svechkaryov, I.V. and Fedorchenko, A.V.}, title = {The use of magnetic methods for investigating the structure evolution in austenitic stainless steels after a long-term service at nuclear power plant units}, journal = {Problems of Atomic Science and Technology}, year = {2009}, volume = {62}, number = {4}, pages = {241-246}, url = {http://vant.kipt.kharkov.ua/ARTICLE/VANT_2009_4/article_2009_4_241.pdf} }
Baranovskiy A., Grechnev G., Panfilov A., Svechkarev I., ZogaŁ O., Czopnik A., Hackemer A.	Anomalous diamagnetism of YbPb3 compound: Pressure effects [Abstract] [BibTeX]	2008	Acta Physica Polonica A Vol. 113(1), pp. 243-246	DOI
Abstract: The effect of a uniform pressure on the magnetic susceptibility was measured for YbPb3 compound, wherein a degeneracy point of the energy bands is located just below the Fermi level and responsible for the anomalous diamagnetism. Theoretical analysis of the experimental data has revealed that a pronounced increase of diamagnetism with pressure is governed by closing the degeneracy point towards the Fermi energy.
BibTeX: @article{Baranovskiy2008243, author = {Baranovskiy, A.E. and Grechnev, G.E. and Panfilov, A.S. and Svechkarev, I.V. and ZogaŁ, O. and Czopnik, A. and Hackemer, A.}, title = {Anomalous diamagnetism of YbPb3 compound: Pressure effects}, journal = {Acta Physica Polonica A}, publisher = {Polish Academy of Sciences}, year = {2008}, volume = {113}, number = {1}, pages = {243-246}, doi = {http://dx.doi.org/10.12693/APhysPolA.113.243} }
Bartoloḿ J., Bartoloḿ E., Eremenko V., Ibulaev V., Sirenko V., Petrusenko Y.	On the magnetic susceptibility of niobium diselenide [Abstract] [BibTeX]	2008	Low Temperature Physics Vol. 34(8), pp. 642-644	DOI
Abstract: The magnetic properties of 2H-Nb Se2, a layered metal with a hexagonal structure of the crystal lattice, are measured, and the change of those properties after irradiation with high-energy electrons is investigated. It is shown that the main part of the magnetic susceptibility comes from the Pauli paramagnetism of free charge carriers. The low-temperature deviations from Pauli paramagnetism are explained by dangling interatomic bonds, which are present in small numbers even in the unirradiated samples.
BibTeX: @article{Bartoloḿ2008642, author = {Bartoloḿ, J. and Bartoloḿ, E. and Eremenko, V.V. and Ibulaev, V.V. and Sirenko, V.A. and Petrusenko, Yu.T.}, title = {On the magnetic susceptibility of niobium diselenide}, journal = {Low Temperature Physics}, year = {2008}, volume = {34}, number = {8}, pages = {642-644}, doi = {http://dx.doi.org/10.1063/1.2967509} }
Beznosov A., Fertman E., Desnenko V.	Charge ordering, internal structural parameters, and magnetic susceptibility of Nd2/3 Ca1/3 Mn O3: Driving forces of a phase transition [Abstract] [BibTeX]	2008	Low Temperature Physics Vol. 34(8), pp. 624-629	DOI
Abstract: The temperature dependences of the long diagonals dMn-O of the Mn O6 octahedron and the magnetic susceptibility of Nd23 Ca13 Mn O3 in the temperature interval 100-290 K are investigated. The functions dMn-O (T) and (T) are found to have anomalies in the charge-ordering range (Tco ≈212 K). The sharp decrease of the diagonal dMn-O2s agrees with phase-transition notions, according to which the spatial modulation of the charge density is due to the modulation of the Mn-Mn bond lengths. The most likely driving forces of the transition are the Peierls lattice instability and Jahn-Teller stability of the Mn O6 octahedron at the Mn3+ ions. The hysteresis of the temperature dependence (T) in the paramagnetic region shows indirectly that structural phase separation occurs together with the transition. The parameters of the function (T) indicate that ferromagnetic clusters consisting of one, two, or three ion pairs Mn3+ - Mn4+ form in the system in the temperature intervals 274 K≤T≤290 K, 224 K≤T≤252 K, and 130 K≤T≤198 K, respectively.
BibTeX: @article{Beznosov2008624, author = {Beznosov, A.B. and Fertman, E.L. and Desnenko, V.A.}, title = {Charge ordering, internal structural parameters, and magnetic susceptibility of Nd2/3 Ca1/3 Mn O3: Driving forces of a phase transition}, journal = {Low Temperature Physics}, year = {2008}, volume = {34}, number = {8}, pages = {624-629}, doi = {http://dx.doi.org/10.1063/1.2967506} }
Dalakova N., Belevtsev B., Beliayev E., Kolesnichenko Y., Panfilov A., Braude I.	Effect of magnetic (phase) inhomogeneities on the conductivity of an antiferromagnetic La2CuO4+δ single crystal at low temperatures [Abstract] [BibTeX]	2008	Bulletin of the Russian Academy of Sciences: Physics Vol. 72(8), pp. 1149-1152	DOI
Abstract: It has been established that, at a strongly nonuniform distribution of oxygen in a La2CuO4+δ single crystal, isolated superconducting inclusions can be formed at an average hole concentration not higher than 0.0024 per copper atom. The behavior of the conductivity in a magnetic field below 20 K is consistent with possible existence of a insulating low-temperature magnetic phase (spin density waves), which is typical of cuprates with excess oxygen.
BibTeX: @article{Dalakova20081149, author = {Dalakova, N.V. and Belevtsev, B.I. and Beliayev, E.Yu. and Kolesnichenko, Yu.A. and Panfilov, A.S. and Braude, I.S.}, title = {Effect of magnetic (phase) inhomogeneities on the conductivity of an antiferromagnetic La2CuO4+δ single crystal at low temperatures}, journal = {Bulletin of the Russian Academy of Sciences: Physics}, year = {2008}, volume = {72}, number = {8}, pages = {1149-1152}, doi = {http://dx.doi.org/10.3103/S1062873808080376} }
Dolya S.	Quasi-exactly solvable models based on special functions [Abstract] [BibTeX]	2008	Journal of Mathematical Physics Vol. 49(5), pp. 053524	DOI
Abstract: We suggest a systematic method of extension of quasiexactly solvable (QES) systems. We construct finite-dimensional subspaces on the basis of special functions (hypergeometric, Airy, Bessel ones) invariant with respect to the action of differential operators of the second order with polynomial coefficients. As an example of physical applications, we show that the known two-photon Rabi Hamiltonian becomes quasiexactly solvable at certain values of parameters when it can be expressed in terms of corresponding QES operators related to the hypergeometric function.
BibTeX: @article{Dolya2008, author = {Dolya, S.N.}, title = {Quasi-exactly solvable models based on special functions}, journal = {Journal of Mathematical Physics}, year = {2008}, volume = {49}, number = {5}, pages = {053524}, doi = {http://dx.doi.org/10.1063/1.2905153} }
Flachbart K., Alekseev P., Grechnev G., Shitsevalova N., Siemensmeyer K., Sluchanko N., Zogal O.	Rare earth dodecaborides-magnetism, superconductivity and other properties [Abstract] [BibTeX]	2008	Rare Earth Research and Applications (Chapter in Book), pp. 79-125	URL
Abstract: B12-cluster compounds have attracted considerable interest in recent years. This is above all due to the unique combination of their physical properties, such as high melting point, hardness, thermal and chemical stability, and rich magnetic properties. Among them, the rare earth dodecaborides (REB12), which crystallize in the NaCl based fcc structure, exhibit a variety of physical properties which result mainly from strong electron correlations of the 4f shell of rare earth ions. Thus e.g., LuB12 with a fully occupied 4f shell is a metal which becomes superconducting below 0.4 K, YbB12 is a Kondo insulator, and TmB12, ErB12, HoB12, DyB12 and TbB12 are metals which order antiferromagnetically in the Kelvin temperature range. In our review we present results of recent investigations performed on these materials. Attention is devoted above all to superconducting and magnetic properties of dodecaborides, however, also their structural, thermal and transport properties, as well as lattice and magnetic excitation spectra are presented and discussed. Results of first principles electronic structure calculations are shown too.
BibTeX: @book{Flachbart200879, author = {Flachbart, K. and Alekseev, P. and Grechnev, G. and Shitsevalova, N. and Siemensmeyer, K. and Sluchanko, N. and Zogal, O.}, title = {Rare earth dodecaborides-magnetism, superconductivity and other properties}, journal = {Rare Earth Research and Applications (Chapter in Book)}, publisher = {Nova Science Publishers, Inc.}, year = {2008}, pages = {79-125}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79551659497&partnerID=40&md5=beff974dd2db2fae1beaa5fc34dac15a} }
Grechnev G., Baranovskiy A., Fil V., Ignatova T., Kolobov I., Logosha A., Shitsevalova N., Filippov V., Eriksson O.	Electronic structure and bulk properties of MB6and MB 12 borides [Abstract] [BibTeX]	2008	Low Temperature Physics Vol. 34(11), pp. 921-929	DOI
Abstract: Ab initio band structure calculations are carried out for the higher borides MB6and MB12. High-precision measurements of the elastic constants are performed for the compounds ZrB12, HoB 12, ErB12, TmB12, LuB12, YB 6 and LaB6 at low temperatures. The bulk properties of the borides are analyzed on the basis of the calculated equations of states and balanced crystal orbital overlap populations. Our calculations indicate that hexaborides with divalent metals, CaB6, SrB6, BaB 6, and YbB6, are semiconductors with small energy gaps. The metallic MB6 hexaborides with trivalent M atoms are found to possess larger bulk moduli values. For dodecaborides the bulk moduli are found to be higher for MB12 with increased filling of the conduction band (ZrB12, HfB12, UB12) in comparison with M 3+B12 compounds. The total energy calculations for different magnetic configurations in YbB12 point to the possibility of antiferromagnetic coupling between Yb3+ ions.
BibTeX: @article{Grechnev2008921, author = {Grechnev, G.E. and Baranovskiy, A.E. and Fil, V.D. and Ignatova, T.V. and Kolobov, I.G. and Logosha, A.V. and Shitsevalova, N.Yu. and Filippov, V.B. and Eriksson, O.}, title = {Electronic structure and bulk properties of MB6and MB 12 borides}, journal = {Low Temperature Physics}, year = {2008}, volume = {34}, number = {11}, pages = {921-929}, doi = {http://dx.doi.org/10.1063/1.3009588} }
Pluzhnikov V., Shitsevalova N., Dukhnenko A., Czopnik A., Nizhankovskii V., Settai R., Onuki Y.	De Haas-van Alphen effect and magnetization in dodecaborides HoB12, ErB12 and TmB12 [Abstract] [BibTeX]	2008	Journal of Magnetism and Magnetic Materials Vol. 320(9), pp. 1597-1604	DOI
Abstract: High-quality HoB12, ErB12 and TmB12 single crystals with the fcc UB12 structure are grown; field dependencies of their magnetization are measured up to 14 T; angular dependences of the magnetization in the (1 0 0) and (1 1 0) planes are calculated, and properties of their Fermi surfaces (FS) are studied using the de Haas-van Alphen (dHvA) effect. The angular dependences of the dHvA frequencies in the (1 0 0) and (1 1 0) planes are obtained and values of their effective cyclotron masses are determined. The oscillation frequencies lie in the range (11.7-127.3)×102 T, and cyclotron masses within the range (0.4-1.45)m0. For ErB12 and TmB12, we found branches in the oscillation spectrum that originated from FS fragments with spins along and opposed to the field, and the energy of the exchange interaction is estimated. Its value for the γ-branch in ErB12 is equal to 8.2 meV, and for the γ-, β- and θ-branches in TmB12; these values are 14.5, 28.5, and 18.3 meV, respectively.
BibTeX: @article{Pluzhnikov20081597, author = {Pluzhnikov, V. and Shitsevalova, N. and Dukhnenko, A. and Czopnik, A. and Nizhankovskii, V. and Settai, R. and Onuki, Y.}, title = {De Haas-van Alphen effect and magnetization in dodecaborides HoB12, ErB12 and TmB12}, journal = {Journal of Magnetism and Magnetic Materials}, year = {2008}, volume = {320}, number = {9}, pages = {1597-1604}, doi = {http://dx.doi.org/10.1016/j.jmmm.2008.01.012} }
Zvyagina G., Zhekov K., Bezmaternykh L., Gudim I., Bilych I., Zvyagin A.	Magnetoelastic effects in terbium ferroborate [Abstract] [BibTeX]	2008	Low Temperature Physics Vol. 34(11), pp. 901-908	DOI
Abstract: The behavior of the elastic moduli and sound absorption in a terbium orthoborate single crystal at low temperatures is studied. The components of the tensor of the elastic moduli of this system are determined. A structural phase transition and a transition of the magnetic subsystem into an antiferromagnetically ordered state appear in the temperature dependences of the sound velocities and absorption. The magnetic field dependences of the velocities of transverse sound exhibit singularities in the form of jumps at a magnetic field equal to the field of the spin-flop transition of the antiferromagnetic subsystem. Theoretical analysis shows that the observed behavior of the acoustic characteristics are associated not with the rare-earth subsystem of ferroborate but rather with the renormalization of the exchange interaction between iron ions as a result of the magnetoelastic coupling.
BibTeX: @article{Zvyagina2008901, author = {Zvyagina, G.A. and Zhekov, K.R. and Bezmaternykh, L.N. and Gudim, I.A. and Bilych, I.V. and Zvyagin, A.A.}, title = {Magnetoelastic effects in terbium ferroborate}, journal = {Low Temperature Physics}, year = {2008}, volume = {34}, number = {11}, pages = {901-908}, doi = {http://dx.doi.org/10.1063/1.3009584} }
Grechnev G.E., Panfilov A.S., Fedorchenko A.V., Svechkarev I.V., Filippov V.B., Lyashchenko A.B., Vasiliev A.N.	Pressure effects on electronic structure and magnetic properties of anisotropic metallic compounds [Abstract] [BibTeX]	2008	High Pressure Physics and Technics Vol. 18(4), pp. 112-118	URL
Abstract: Pressure effects on electronic structure and magnetic properties of anisotropic metallic materials (CrB2, FeGe2, LaFeAsO) are investigated. Magnetic susceptibilities of CrB2 and FeGe2 compounds were studied under hydrostatic pressure at fixed temperatures, 77 and 300 K. In order to analyze the experimental magnetovolume effects, the electronic structures were calculated ab initio in external magnetic field as a function of atomic volume by employing a full-potential LMTO method. The calculated field-induced magnetic moments and their volume derivatives compare favorably with the experimental pressure effects in magnetic properties of CrB2 and FeGe2. The main role of pressure in high-Tc superconductivity of LaFeAsO is found to reduce density of states at the Fermi level and to suppress ferromagnetic spin fluctuations.
BibTeX: @article{grechnev2008, author = {Grechnev, G. E. and Panfilov, A. S. and Fedorchenko, A. V. and Svechkarev, I. V. and Filippov, V. B. and Lyashchenko, A. B. and Vasiliev, A. N.}, title = {Pressure effects on electronic structure and magnetic properties of anisotropic metallic compounds}, journal = {High Pressure Physics and Technics}, year = {2008}, volume = {18}, number = {4}, pages = {112-118}, url = {http://www.fti.dn.ua/site/en/ftvd-journal/journal-content/ftvd-v18-4/} }
Baranovskiy A., Grechnev G., Panfilov A., Svechkarev I., Zogal O., Czopnik A., Hackemer A.	Anomalous magnetism of YbPb3: The effect of pressure [Abstract] [BibTeX]	2007	Low Temperature Physics Vol. 33(12), pp. 1028-1032	DOI
Abstract: In the compound YbPb3, the anomalous diamagnetism of which is due to the presence of a point of degeneracy of the energy bands near the Fermi level, the influence of hydrostatic pressure of up to 2 kbar on the magnetic susceptibility at fixed temperatures of 78 and 300 K. A theoretical analysis of the experimental data shows that appreciable growth of the diamagnetism under pressure comes about because a point of band degeneracy is approaching the Fermi level. The initial position of the band with respect to the Fermi level is refined, and its dependence on the atomic volume is determined.
BibTeX: @article{Baranovskiy20071028, author = {Baranovskiy, A.E. and Grechnev, G.E. and Panfilov, A.S. and Svechkarev, I.V. and Zogal, O. and Czopnik, A. and Hackemer, A.}, title = {Anomalous magnetism of YbPb3: The effect of pressure}, journal = {Low Temperature Physics}, year = {2007}, volume = {33}, number = {12}, pages = {1028-1032}, doi = {http://dx.doi.org/10.1063/1.2747082} }
Baranovskiy A., Grechnev G., Fil V., Ignatova T., Logosha A., Panfilov A., Svechkarev I., Shitsevalova N., Filippov V., Eriksson O.	Electronic structure, bulk and magnetic properties of MB6 and MB12 borides [Abstract] [BibTeX]	2007	Journal of Alloys and Compounds Vol. 442(1-2 SPEC. ISS.), pp. 228-230	DOI
Abstract: The bulk and magnetic properties of MB6 and MB12 were investigated on the basis of first principles electronic structure calculations. The elastic constants were measured for ZrB12, HoB12, ErB12, TmB12, LuB12, YB6 and LaB6 compounds at low temperatures. The calculated equations of states and balanced crystal orbital overlap populations have allowed to analyse bonding and magnetic properties of MB6 and MB12.
BibTeX: @article{Baranovskiy2007228, author = {Baranovskiy, A.E. and Grechnev, G.E. and Fil, V.D. and Ignatova, T.V. and Logosha, A.V. and Panfilov, A.S. and Svechkarev, I.V. and Shitsevalova, N.Yu. and Filippov, V.B. and Eriksson, O.}, title = {Electronic structure, bulk and magnetic properties of MB6 and MB12 borides}, journal = {Journal of Alloys and Compounds}, year = {2007}, volume = {442}, number = {1-2 SPEC. ISS.}, pages = {228-230}, doi = {http://dx.doi.org/10.1016/j.jallcom.2006.07.142} }
Eremenko V., Kurnosov V., Peschanskii A., Fomin V., Khats'ko E.	Raman scattering of light by low-energy electronic excitations of the Tb3+ ion in the crystal KTb (WO4) 2 [Abstract] [BibTeX]	2007	Low Temperature Physics Vol. 33(11), pp. 915-919	DOI
Abstract: The Raman scattering spectrum in a KTb (WO4) 2 crystal is investigated in the frequency range 3-950 cm-1 at temperatures 5, 80, and 300 K. The symmetry of all 36 vibrational excitations predicted by group-theoretical analysis is determined. The temperature behavior of the scattering spectra indicates that there is no phase transition in the temperature interval studied. Low-energy electronic transitions are found between the levels of the ground-state multiplet F67 of Tb3+ split in a crystal field with symmetry C2. It is determined that the first excited electronic quasidoublet consists of two singlet levels with different symmetry and is separated by a quite high (∼75 cm-1) energy from the ground-state quasidoublet. The behavior of all experimentally observed levels in external magnetic fields H⊥ C2 and H C2 is investigated. The results confirm that a virtually pure case of Ising anisotropy is realized at low temperatures and the magnet studied in the present work can be regarded as a system of two-level magnetic ions.
BibTeX: @article{Eremenko2007915, author = {Eremenko, V.V. and Kurnosov, V.S. and Peschanskii, A.V. and Fomin, V.I. and Khats'ko, E.N.}, title = {Raman scattering of light by low-energy electronic excitations of the Tb3+ ion in the crystal KTb (WO4) 2}, journal = {Low Temperature Physics}, year = {2007}, volume = {33}, number = {11}, pages = {915-919}, doi = {http://dx.doi.org/10.1063/1.2747049} }
Fertman E., Beznosov A., Desnenko V., Pal-Val L., Pal-Val P., Khalyavin D.	Singularities of magnetic and elastic characteristics of La2/3Ba1/3MnO3: Analysis of martensitic kinetics [Abstract] [BibTeX]	2007	Journal of Magnetism and Magnetic Materials Vol. 308(2), pp. 278-283	DOI
Abstract: A coordinated temperature behavior of magnetic susceptibility and internal friction has been observed in the La2/3Ba1/3MnO3 manganite in the temperature region of the crystal phase separation 5-340 K. Stepwise temperature behavior of the susceptibility of the single crystal sample and corresponding singular behavior of the internal friction in the polycrystalline manganite have been found. These small-scale features of the temperature dependences of the susceptibility and the internal friction are considered to be a reflection of martensitic kinetics of the structural phase transformation R3̄c↔Imma in the 200 K temperature region.
BibTeX: @article{Fertman2007278, author = {Fertman, E.L. and Beznosov, A.B. and Desnenko, V.A. and Pal-Val, L.N. and Pal-Val, P.P. and Khalyavin, D.D.}, title = {Singularities of magnetic and elastic characteristics of La2/3Ba1/3MnO3: Analysis of martensitic kinetics}, journal = {Journal of Magnetism and Magnetic Materials}, year = {2007}, volume = {308}, number = {2}, pages = {278-283}, doi = {http://dx.doi.org/10.1016/j.jmmm.2006.06.001} }
Fil V., Ignatova T., Burma N., Petrishin A., Fil D., Shitsevalova N.	Mass of an Abrikosov vortex [Abstract] [BibTeX]	2007	Low Temperature Physics Vol. 33(12), pp. 1019-1022	DOI
Abstract: In the excitation of a vortex lattice in the mixed phase of Yb6 single crystals by an elastic wave, the dynamic response is found to have a negative component quadratic in the frequency; we associate this component with the vortex mass. The value of the effect is in catastrophic contradiction with the existing theoretical estimates.
BibTeX: @article{Fil20071019, author = {Fil, V.D. and Ignatova, T.V. and Burma, N.G. and Petrishin, A.I. and Fil, D.V. and Shitsevalova, N.Yu.}, title = {Mass of an Abrikosov vortex}, journal = {Low Temperature Physics}, year = {2007}, volume = {33}, number = {12}, pages = {1019-1022}, doi = {http://dx.doi.org/10.1063/1.2747080} }
Golubkov A., Parfen'eva L., Smirnov I., Wlosewicz D., Misiorek H., Mucha J., Jezowski A., Krivchikov A., Zvyagina G.	Specific heat and velocity of sound in a moderate heavy-fermion compound YbZnCu4 [Abstract] [BibTeX]	2007	Physics of the Solid State Vol. 49(2), pp. 200-204	DOI
Abstract: The specific heat at a constant pressure (Cp) and the velocity of sound (v) are measured for a moderate heavy-fermion compound YbZnCu 4 in the temperature range 3.5-250 K and at 77 K, respectively. The experimental values of Cp and v obtained in this study and the phonon thermal conductivity previously measured in the temperature range 5-300 K are used to calculate the phonon mean free path l for this compound. The temperature dependence of the phonon mean free path l thus determined is characteristic of classical amorphous materials.
BibTeX: @article{Golubkov2007200, author = {Golubkov, A.V. and Parfen'eva, L.S. and Smirnov, I.A. and Wlosewicz, D. and Misiorek, H. and Mucha, J. and Jezowski, A. and Krivchikov, A.I. and Zvyagina, G.A.}, title = {Specific heat and velocity of sound in a moderate heavy-fermion compound YbZnCu4}, journal = {Physics of the Solid State}, year = {2007}, volume = {49}, number = {2}, pages = {200-204}, doi = {http://dx.doi.org/10.1134/S1063783407020023} }
Golubkov A., Parfen'eva L., Smirnov I., Wlosewicz D., Misiorek H., Mucha J., Jezowski A., Krivchikov A., Zvyagina G., Bilich I.	Heat capacity and velocity of sound in the YbMgCu4 "light" heavy-fermion system [Abstract] [BibTeX]	2007	Physics of the Solid State Vol. 49(11), pp. 2042-2046	DOI
Abstract: This paper reports on a measurement of the heat capacity at constant pressure (C p ) in the temperature range 3-320 K and the sound velocity (v) at 77 K for the "light" heavy-fermion compound YbMgCu4. The present experimental data on C p and v of YbMgCu4, combined with our earlier phonon thermal conductivity data for YbMgCu4 in the range 5-300 K, have been used to calculate the phonon mean free path l in this compound. The temperature dependence of l obtained is found to be characteristic of classical amorphous materials.
BibTeX: @article{Golubkov20072042, author = {Golubkov, A.V. and Parfen'eva, L.S. and Smirnov, I.A. and Wlosewicz, D. and Misiorek, H. and Mucha, J. and Jezowski, A. and Krivchikov, A.I. and Zvyagina, G.A. and Bilich, I.B.}, title = {Heat capacity and velocity of sound in the YbMgCu4 "light" heavy-fermion system}, journal = {Physics of the Solid State}, year = {2007}, volume = {49}, number = {11}, pages = {2042-2046}, doi = {http://dx.doi.org/10.1134/S1063783407110042} }
Kontrym-Sznajd G., Samsel-Czekała M., Grechnev G., Sormann H.	Fermi surface of ErGa3 [Abstract] [BibTeX]	2007	Physica Status Solidi (C) Current Topics in Solid State Physics Vol. 4(10), pp. 3879-3882	DOI
Abstract: The Fermi surface (FS) in paramagnetic ErGa3 is estimated by various band structure methods: linear muffin-tin orbital (LMTO) in the atomic sphere approximation (ASA) and three new codes contained full potential (FP) instead of ASA, namely FP-LMTO, FP linear augmented plane wave (FLAPW), and FP local orbitais (FPLO) methods. Three dimensional (3D) electron-positron (e-p) momentum densities ρ(p) are reconstructed from two dimensional (2D) angular correlation of annihilation radiation (ACAR) spectra measured for paramagnetic ErGa3. Reconstructed densities in the extended p-space, folded into the reduced k-space, are compared with the theoretical results. Unfortunately, none of these modern FP codes is able to give satisfying description of the experimental data that are in perfect agreement with previous LMTO-ASA results.
BibTeX: @article{Kontrym-Sznajd20073879, author = {Kontrym-Sznajd, G. and Samsel-Czekała, M. and Grechnev, G.E. and Sormann, H.}, title = {Fermi surface of ErGa3}, journal = {Physica Status Solidi (C) Current Topics in Solid State Physics}, year = {2007}, volume = {4}, number = {10}, pages = {3879-3882}, doi = {http://dx.doi.org/10.1002/pssc.200675770} }
Pluzhnikov V., Svechkarev I., Dukhnenko A., Levchenko A., Filippov V., Chopnik A.	De Haas-van Alphen effect in the diborides ScB2, ZrB2, and HfB2 [Abstract] [BibTeX]	2007	Low Temperature Physics Vol. 33(4), pp. 350-354	DOI
Abstract: ScB2, ZrB2, and HfB2 single crystals with hexagonal structure were grown and the properties of the Fermi surface of these compounds were studied using the de Haas-van Alphen effect (dHvA). The angular dependences of the frequencies of the dHvA oscillations in the planes (10 1- 0), (11 2- 0), and (0001) and the values of their effective cyclotron masses were measured. The frequencies of the oscillations found lie in the interval (0.96-28.2)× 102 T and the measured cyclotron masses lie in the range (0.09-0.87) m0. The values of the electron-phonon interaction constant λ on different sections of Fermi surface of ZrB2 were determined. The value of the constant λ ranges from 0.05-0.16.
BibTeX: @article{Pluzhnikov2007350, author = {Pluzhnikov, V.B. and Svechkarev, I.V. and Dukhnenko, A.V. and Levchenko, A.V. and Filippov, V.B. and Chopnik, A.}, title = {De Haas-van Alphen effect in the diborides ScB2, ZrB2, and HfB2}, journal = {Low Temperature Physics}, year = {2007}, volume = {33}, number = {4}, pages = {350-354}, doi = {http://dx.doi.org/10.1063/1.2720083} }
Smirnov I., Smirnov B., Misiorek H., Jezowski A., De Arellano-Lopez A., Martinez-Fernandez J., Varela-Feria F., Krivchikov A., Zviagina G., Zhekov K.	Heat capacity and velocity of sound in the SiC/Si biomorphic composite [Abstract] [BibTeX]	2007	Physics of the Solid State Vol. 49(10), pp. 1839-1844	DOI
Abstract: The specific heat at constant pressure and the velocity of sound in the SiC/Si biomorphic composite prepared from white eucalyptus wood are measured in the range 3.5-65 K and at 77 K, respectively. The heat capacity of the SiC/Si sample under investigation is calculated within three proposed models according to the Kopp-Neumann additivity rule.
BibTeX: @article{Smirnov20071839, author = {Smirnov, I.A. and Smirnov, B.I. and Misiorek, H. and Jezowski, A. and De Arellano-Lopez, A.R. and Martinez-Fernandez, J. and Varela-Feria, F.M. and Krivchikov, A.I. and Zviagina, G.A. and Zhekov, K.R.}, title = {Heat capacity and velocity of sound in the SiC/Si biomorphic composite}, journal = {Physics of the Solid State}, year = {2007}, volume = {49}, number = {10}, pages = {1839-1844}, doi = {http://dx.doi.org/10.1134/S1063783407100058} }
Zvyagin G., Chupis I., Fil' V., Zhekov K., Avramenko Y., Lee S.-I.	Magnetoelastic interaction and acoustic nonreciprocity in Gd Ni2 B2 C [Abstract] [BibTeX]	2007	Low Temperature Physics Vol. 33(11), pp. 952-956	DOI
Abstract: Ultrasonic investigations of a gadolinium borocarbide single crystal have been performed. It has been found that the acoustic characteristics are highly sensitive to magnetic phase transformations. This sensitivity is due to the interaction of sound waves with the antiferromagnetic domain structure. Acoustic "nonreciprocity" of the same nature has also been observed. Arguments for the existence of weak ferromagnetism in Gd Ni2 B2 C are presented.
BibTeX: @article{Zvyagin2007952, author = {Zvyagin, G.A. and Chupis, I.E. and Fil', V.D. and Zhekov, K.R. and Avramenko, Yu.A. and Lee, S.-I.}, title = {Magnetoelastic interaction and acoustic nonreciprocity in Gd Ni2 B2 C}, journal = {Low Temperature Physics}, year = {2007}, volume = {33}, number = {11}, pages = {952-956}, doi = {http://dx.doi.org/10.1063/1.2747072} }
Avdeenko A., Pyshkin O., Eremenko V., Strzhemechny M., Buravtseva L., Romashkin R.	Photoluminescence of ortho-bromobenzophenone [Abstract] [BibTeX]	2006	Low Temperature Physics Vol. 32(11), pp. 1028-1034	DOI
Abstract: Phosphorescence spectra of crystalline ortho-bromobenzophenone (2-bromobenzophenone, 2BrBP) were measured from 1.6 K to room temperature. A cardinal emission mechanism crossover occurs within this temperature range. At low temperature the phosphorescence spectrum is a superposition of two similar sets of equidistant bands spaced by the CO stretch frequency. We ascribe these two sets to the emission of two different conformers, one of which is metastable and does not manifest itself above approximately 70 K. The presence of two conformers is explained by the fact that the 2BrBP molecule deforms considerably upon excitation. The emission from the stable conformer survives up to approximately 140 K or even higher. At roughly 60 K and higher, another type of emission reveals itself in the shape of two very broad, partly overlapping bands, which gains in intensity with increasing temperature. Above 150 K only this two-hump feature is observed in phosphorescence spectra. Additional phosphorescence experiments were carried out to elucidate the nature of this spectrum, including phosphorescence measurements of 2BrBP in ethanol solutions as well as time-resolved and varying-excitation-intensity measurements from crystals. Based on results of all the experiments reported here and on our own single-crystal x-ray structure data we conclude that the above two-band spectrum recorded near room temperature is due to the emission of single-photon bimolecular triplet excimer formed by the carbonyl groups of two neighboring 2-bromobenzophenone molecules. This is the first time that a bimolecular excimer has been observed and reliably identified in a benzophenone derivative solid.
BibTeX: @article{Avdeenko20061028, author = {Avdeenko, A.A. and Pyshkin, O.S. and Eremenko, V.V. and Strzhemechny, M.A. and Buravtseva, L.M. and Romashkin, R.V.}, title = {Photoluminescence of ortho-bromobenzophenone}, journal = {Low Temperature Physics}, year = {2006}, volume = {32}, number = {11}, pages = {1028-1034}, doi = {http://dx.doi.org/10.1063/1.2389009} }
Baranovskiy A., Grechnev G., Logosha A., Svechkarev I., Filippov V., Shitsevalova N., Zogał O., Eriksson O.	Electronic spectra and magnetic properties of RB6, RB 12 and RB2C2 borides [Abstract] [BibTeX]	2006	Physica Status Solidi C: Conferences Vol. 3(1), pp. 229-232	DOI
Abstract: The electronic structures of RB6, RB12 and RB 2C2 borides are studied ab initio by using the full-potential linear muffin-tin orbital method. This study includes the promising materials for spin electronics with reported high temperature ferromagnetism, namely, doped divalent hexaborides CaB6, SrB 6, BaB6, and the CaB2C2 compound, as well as Kondo semiconductors, SmB6 and YbB12. For CaBe and SrB6 a semiconducting band structure has been obtained, whereas a semimetallic ground state is revealed for CaB2C2 and doped hexaborides. For YB6, LaB6, CaB2C 2 and the semimetallic Ba1-xLaxB6 alloys we have performed spin-polarized band structure calculations in an external field to evaluate the induced spin and orbital magnetic moments. These calculations indicate a feasibility of the field-induced weak ferromagnetic phase in ~CaB2C2 and the La doped hexaborides. The LSDA and GGA calculations for different spin configurations of YbB12 point to a possibility of antiferromagnetic coupling between Yb3+ ions. For SmB6 and YbB12 our LSDA, GGA, and LSDA+U calculations have not revealed the hybridization gap for configurations with trivalent Sm3+ and Yb3+.
BibTeX: @conference{Baranovskiy2006229, author = {Baranovskiy, A.E. and Grechnev, G.E. and Logosha, A.V. and Svechkarev, I.V. and Filippov, V.B. and Shitsevalova, N.Yu. and Zogał, O.J. and Eriksson, O.}, title = {Electronic spectra and magnetic properties of RB6, RB 12 and RB2C2 borides}, journal = {Physica Status Solidi C: Conferences}, year = {2006}, volume = {3}, number = {1}, pages = {229-232}, doi = {http://dx.doi.org/10.1002/pssc.200562489} }
Baranovskiy A., Grechnev G., Svechkarev I.	Features of the electronic spectrum and anomalous magnetism in the compounds YbPb3, YbSn3, CaPb3, and CaSn 3 [Abstract] [BibTeX]	2006	Low Temperature Physics Vol. 32(8), pp. 849-856	DOI
Abstract: A theoretical study is made of the features of the band structure and magnetic susceptibility χ in the isovalent compounds YbP3, YbSn3, CaPb3, and CaSn3 with the AuCu 3 lattice. It is shown that their anomalous, strongly temperature-dependent diamagnetism is due to the presence of points of degeneracy of the bands near the Fermi level. Analysis of the behavior of χ(T) gives refined values of the energies of the degeneracy points as precision reference marks in the band spectrum of these compounds.
BibTeX: @article{Baranovskiy2006849, author = {Baranovskiy, A.E. and Grechnev, G.E. and Svechkarev, I.V.}, title = {Features of the electronic spectrum and anomalous magnetism in the compounds YbPb3, YbSn3, CaPb3, and CaSn 3}, journal = {Low Temperature Physics}, year = {2006}, volume = {32}, number = {8}, pages = {849-856}, doi = {http://dx.doi.org/10.1063/1.2356841} }
Belevtsev B., Zvyagina G., Zhekov K., Kolobov I., Beliayev E., Panfilov A., Galtsov N., Prokhvatilov A., Fink-Finowicki J.	Influence of magnetic field on the paramagnetic-ferromagnetic transition in a La1-x Cax Mn O3 (x≈0.25) crystal: Ultrasonic and transport studies [Abstract] [BibTeX]	2006	Physical Review B - Condensed Matter and Materials Physics Vol. 74(5), pp. 054427	DOI
Abstract: The ultrasonic properties of La1-x Cax Mn O3 (x≈0.25) with the Curie temperature TC about 200 K are studied. Temperature dependences of longitudinal and transverse sound velocities were measured in zero magnetic field and for different constant magnetic fields as well. The ultrasonic study is supported by magnetic, resistive, magnetoresistive, structural, and other measurements of the sample that facilitate interpretation of the results obtained. The magnetic-field influence on sound properties found in this study presents some interesting features of the interplay between the elastic and magnetic properties of these compounds. It is shown that the paramagnetic-ferromagnetic transition in the sample studied is first order, but can become second order under the influence of applied magnetic field.
BibTeX: @article{Belevtsev2006, author = {Belevtsev, B.I. and Zvyagina, G.A. and Zhekov, K.R. and Kolobov, I.G. and Beliayev, E.Yu. and Panfilov, A.S. and Galtsov, N.N. and Prokhvatilov, A.I. and Fink-Finowicki, J.}, title = {Influence of magnetic field on the paramagnetic-ferromagnetic transition in a La1-x Cax Mn O3 (x≈0.25) crystal: Ultrasonic and transport studies}, journal = {Physical Review B - Condensed Matter and Materials Physics}, year = {2006}, volume = {74}, number = {5}, pages = {054427}, doi = {http://dx.doi.org/10.1103/PhysRevB.74.054427} }
Burma N., Petruishin A., Ryabukha N., Fil V.	Experimental observation of electromagnetic beam waves [Abstract] [BibTeX]	2006	Low Temperature Physics Vol. 32(12), pp. 1147-1153	DOI
Abstract: The electromagnetic transparency of high-purity gallium single crystals at zero magnetic field is investigated at temperatures of 1.7-4.2 K. Under conditions of strong temporal dispersion beam electromagnetic waves are observed which are due to electrons from the flattenings of the Fermi surface. The velocities, damping, moduli, and initial phases of the excitation coefficients are measured and the frequency dependence of the damping and the dependence of the phase velocity on the relaxation time are obtained. Beam waves, unlike ballistic (quasiwave) transport of electromagnetic field, are characterized by the presence of Landau damping and significant decrease of the phase velocity with decreasing relaxation time.
BibTeX: @article{Burma20061147, author = {Burma, N.G. and Petruishin, A.I. and Ryabukha, N.A. and Fil, V.D.}, title = {Experimental observation of electromagnetic beam waves}, journal = {Low Temperature Physics}, year = {2006}, volume = {32}, number = {12}, pages = {1147-1153}, doi = {http://dx.doi.org/10.1063/1.2400692} }
Eremenko V., Gospodarev I., Ibulaev V., Sirenko V., Feodosev S., Shvedun M.	Anisotropy of the temperature dependence of the lattice parameters of EuBa2Cu3O7-d in the quasiharmonic limit [Abstract] [BibTeX]	2006	Low Temperature Physics Vol. 32(12), pp. 1189-1193	DOI
Abstract: An x-ray diffraction analysis of the compound Eu Ba2 Cu3 O7-δ is carried out in the temperature range 20-300 K. At all temperatures of measurement the structure is described in the orthorhombic system. Nonmonotonic growth of the crystal lattice parameter c with decreasing temperature is observed in the interval 150-20 K, and substantial features of the temperature dependence of the coefficient of linear thermal expansion appear below the Debye temperature. The results of the experiment are in complete agreement with the conclusions of a microscopic treatment of the vibrations of the atoms of the BaO and europium layers and also the Cu-O chains.
BibTeX: @article{Eremenko20061189, author = {Eremenko, V.V. and Gospodarev, I.A. and Ibulaev, V.V. and Sirenko, V.A. and Feodosev, S.B. and Shvedun, M.Yu.}, title = {Anisotropy of the temperature dependence of the lattice parameters of EuBa2Cu3O7-d in the quasiharmonic limit}, journal = {Low Temperature Physics}, year = {2006}, volume = {32}, number = {12}, pages = {1189-1193}, doi = {http://dx.doi.org/10.1063/1.2400698} }
Eremenko V., Feodosyev S., Gospodarev I., Ibulaev V., McCallum R., Shvedun M., Sirenko V.	Negative expansion of Eu(Ba1-xLax)2Cu 3O7-d compounds [Abstract] [BibTeX]	2006	AIP Conference Proceedings Vol. 850, pp. 489-490	DOI
Abstract: Variation of crystal-lattice parameters with temperature was studied by means of X-ray diffraction technique on the perovskite-like structures with Ba- substitution for light rare earth. Anisotropic negative thermal expansion was observed and explained within the "membrane effect" model proving its lattice origin.
BibTeX: @conference{Eremenko2006489, author = {Eremenko, V. and Feodosyev, S. and Gospodarev, I. and Ibulaev, V. and McCallum, R.W. and Shvedun, M. and Sirenko, V.}, title = {Negative expansion of Eu(Ba1-xLax)2Cu 3O7-d compounds}, journal = {AIP Conference Proceedings}, year = {2006}, volume = {850}, pages = {489-490}, doi = {http://dx.doi.org/10.1063/1.2354798} }
Eremenko V., Gammel P., Remenyi G., Sirenko V., Panfilov A., Desnenko V., Ibulaev V., Fedorchenko A.	Magnetostriction of charge density wave superconductor [Abstract] [BibTeX]	2006	AIP Conference Proceedings Vol. 850, pp. 979-980	DOI
Abstract: Single crystals of layered niobium diselenide (2H-NbSe2) compound with hexagonally packed layers were studied in a range of temperature 1.5-300 K by measuring magnetostricrtion and magnetization in field up to 20 T. The data are compared with magnetic susceptibility measurements. Specific features of measured temperature and field dependences were observed near CDW transition temperature (32.5 K) and superconducting transition (7.2 K), sensitive to magnetic field direction and strength.
BibTeX: @conference{Eremenko2006979, author = {Eremenko, V. and Gammel, P. and Remenyi, G. and Sirenko, V. and Panfilov, A. and Desnenko, V. and Ibulaev, V. and Fedorchenko, A.}, title = {Magnetostriction of charge density wave superconductor}, journal = {AIP Conference Proceedings}, year = {2006}, volume = {850}, pages = {979-980}, doi = {http://dx.doi.org/10.1063/1.2355033} }
Fil V., Fil D., Zholobenko A., Burma N., Avramenko Y., Kim J., Choi S., Lee S.	Magnus force and acoustic Stewart-Tolman effect in type-II superconductors [Abstract] [BibTeX]	2006	Europhysics Letters Vol. 76(3), pp. 484-490	DOI
Abstract: We present an acoustic method for the study of the effective Magnus force in type-II superconductors. The method is based on the measurement of the amplitude and the phase of the electromagnetic field radiated by a superconductor due to vortex oscillations excited by a transverse elastic wave. The method does not require the flux flow regime and allows us to measure the Magnus force almost everywhere over the range of the existence of the mixed state. We have measured the field dependence of the Magnus force in nonmagnetic borocarbides (electron-type conductors) and in Nb (hole-type conductor). It is found that in borocarbides the sign of the Magnus force in the mixed state has the same sign as the Lorentz force acting on charge carriers in the normal state, and its value (counted per one vortex of unit length) has only a weak dependence on the magnetic field. In Nb the gyroscopic force changes its sign under transition from the normal to the mixed state. The essential point of the method is the registration of the electromagnetic radiation from the superconductor at zero magnetic field caused by the acoustic Stewart-Tolman effect.
BibTeX: @article{Fil2006484, author = {Fil, V.D. and Fil, D.V. and Zholobenko, A.N. and Burma, N.G. and Avramenko, Yu.A. and Kim, J.D. and Choi, S.M. and Lee, S.I.}, title = {Magnus force and acoustic Stewart-Tolman effect in type-II superconductors}, journal = {Europhysics Letters}, year = {2006}, volume = {76}, number = {3}, pages = {484-490}, doi = {http://dx.doi.org/10.1209/epl/i2006-10298-x} }
Grechnev G., Logosha A., Svechkarev I., Kuchin A., Kulikov Y., Korzhavyi P., Eriksson O.	Electronic structure and magnetic properties of RNi5-xCu x alloys (R=Y, La, Ce) [Abstract] [BibTeX]	2006	Low Temperature Physics Vol. 32(12), pp. 1140-1146	DOI
Abstract: A study is made of the electronic structure and magnetic properties of R N5-x Cux alloys (R=Y, La, Ce). The influence of substitution of nickel by copper on the features of the band structure and behavior of the magnetic susceptibility of these alloys is investigated. An analysis is made of the electronic states and interactions responsible for the magnetic properties of R Ni5-x Cux alloys.
BibTeX: @article{Grechnev20061140, author = {Grechnev, G.E. and Logosha, A.V. and Svechkarev, I.V. and Kuchin, A.G. and Kulikov, Yu.A. and Korzhavyi, P.A. and Eriksson, O.}, title = {Electronic structure and magnetic properties of RNi5-xCu x alloys (R=Y, La, Ce)}, journal = {Low Temperature Physics}, year = {2006}, volume = {32}, number = {12}, pages = {1140-1146}, doi = {http://dx.doi.org/10.1063/1.2400691} }
Mantytskaya O., Kolesova I., Troyanchuk I., Szymczak H., Sirenko V., Eremenko V.	Influence of oxygen nonstoichiometry on the crystal structure and magnetic properties of the cation-deficient manganites Pr0.9MnOx (2.85 <x< 2.90) [Abstract] [BibTeX]	2006	Low Temperature Physics Vol. 32(7), pp. 665-669	DOI
Abstract: X-ray diffraction and magnetic studies of the Pr0.9MnO x system are carried out for different oxygen concentrations in the interval 2.85 <x< 2.90. It is found that an antiferromagnet-ferromagnet phase transition occurs with increasing oxygen concentration in the solid solutions of the series Pr0.9MnOx The crystal structure and magnetic properties of the most highly reduced sample Pr 0.9MnO2.85 are close to those of the stoichiometric manganite PrMnO3. Pr0.9MnO2.90 is a ferromagnetic insulator with Tc= 120 K. In this sample a transition from an orbitally ordered phase to an orbitally disordered phase occurs over a wide range of temperatures. The properties of the samples are explained by the hypothesis that a portion of the praseodymium ions (up to 5%) can be substituted by trivalent manganese ions without forming oxygen vacancies. Upon oxidation of the samples, vacancies of the praseodymium cations appear, while the oxygen skeleton is preserved.
BibTeX: @article{Mantytskaya2006665, author = {Mantytskaya, O.S. and Kolesova, I.M. and Troyanchuk, I.O. and Szymczak, H. and Sirenko, V.A. and Eremenko, V.V.}, title = {Influence of oxygen nonstoichiometry on the crystal structure and magnetic properties of the cation-deficient manganites Pr0.9MnOx (2.85 <x< 2.90)}, journal = {Low Temperature Physics}, year = {2006}, volume = {32}, number = {7}, pages = {665-669}, doi = {http://dx.doi.org/10.1063/1.2216252} }
Mihalik M., Kavečanský V., Panfilov A., Wochowski K., Troć R.	Effects of alloying and pressure on magnetic properties of (U1-xThx)3Al2M3 (M = Si and Ge) [Abstract] [BibTeX]	2006	Journal of Alloys and Compounds Vol. 421(1-2), pp. 8-11	DOI
Abstract: The pressure derivative dTC/dP was evaluated from measurements of the paramagnetic susceptibility of (U0.95Th0.05)3Al2M 3 alloys (M = Si and Ge) under uniform pressure in order to estimate the chemical pressure effect on TC. Our results show that the decrease of the unit cell volume under pressure is followed by decrease of Θ (≈TC). As it was evaluated from X-ray study, the substitution of U by Th leads to a nearly linear increase of the unit cell volume V, i.e. to negative chemical pressure effect. The chemical pressure effect appears to be of the same order as the total change of TC induced by hydrostatic pressure in these alloys but opposite in sign. The decrease of TC with alloying is presumably caused by a change of 5f state hybridization with conduction electrons.
BibTeX: @article{Mihalik20068, author = {Mihalik, M. and Kavečanský, V. and Panfilov, A.S. and Wochowski, K. and Troć, R.}, title = {Effects of alloying and pressure on magnetic properties of (U1-xThx)3Al2M3 (M = Si and Ge)}, journal = {Journal of Alloys and Compounds}, year = {2006}, volume = {421}, number = {1-2}, pages = {8-11}, doi = {http://dx.doi.org/10.1016/j.jallcom.2005.11.005} }
Strzhemechny M., Avdeenko A., Eremenko V., Pyshkin O., Buravtseva L.	Observation of triplet excimer emission in 2-bromobenzophenone [Abstract] [BibTeX]	2006	Chemical Physics Letters Vol. 431(4-6), pp. 300-302	DOI
Abstract: Phosphorescence spectra of 2-bromobenzophenone (2Br-BP) crystals were measured from 70 K to room temperature. A capital crossover in the emission mechanism takes place within this temperature range, leaving at room temperature only a broad two-hump feature. Additional phosphorescence experiments, carried out to understand the nature of this spectrum, include measurements from 2Br-BP solutions in ethanol as well as time-resolved and varying-excitation-intensity measurements from crystals. Based on results of these experiments and on our own single-crystal X-ray structure data, we conclude that the above two-band spectrum recorded near room temperature is due to the emission of single-photon bi-molecular triplet excimer formed by the carbonyl groups of two neighbor 2-bromobenzophenone molecules.
BibTeX: @article{Strzhemechny2006300, author = {Strzhemechny, M.A. and Avdeenko, A.A. and Eremenko, V.V. and Pyshkin, O.S. and Buravtseva, L.M.}, title = {Observation of triplet excimer emission in 2-bromobenzophenone}, journal = {Chemical Physics Letters}, year = {2006}, volume = {431}, number = {4-6}, pages = {300-302}, doi = {http://dx.doi.org/10.1016/j.cplett.2006.09.097} }
Zvyagin A., Zvyagina G.	Sound pumping in an alternating quantum spin chain [Abstract] [BibTeX]	2006	Physical Review B - Condensed Matter and Materials Physics Vol. 73(10), pp. 104422	DOI
Abstract: The pumping of the energy of a longitudinal sound by a quantum spin chain with the alternation of coupling constants is studied theoretically. It is shown that the power of the sound wave, absorbed by the dimerized spin chain, is zero in the dynamical regime, i.e., at times, smaller than relaxation times. In the steady-state regime, for times, larger than the relaxation time, the dimerized quantum spin chain can absorb the power of the sound. We have shown that the absorption of the sound exists when the frequency of the wave is between two threshold values, related to two critical fields, at which quantum phase transitions take place. Contrary, the calculated magnetic field dependence of the absorbed power of the sound does not clearly manifest two critical fields. Nevertheless, we have shown that it is possible to extract the information about the value of the field, at which the spin gap of low-lying excitations is closed, from the temperature dependence of the absorption of the longitudinal sound.
BibTeX: @article{Zvyagin2006, author = {Zvyagin, A.A. and Zvyagina, G.A.}, title = {Sound pumping in an alternating quantum spin chain}, journal = {Physical Review B - Condensed Matter and Materials Physics}, year = {2006}, volume = {73}, number = {10}, pages = {104422}, doi = {http://dx.doi.org/10.1103/PhysRevB.73.104422} }
Czopnik A., Shitsevalova N., Pluzhnikov V., Krivchikov A., Paderno Y., Onuki Y.	Low-temperature thermal properties of yttrium and lutetium dodecaborides [Abstract] [BibTeX]	2005	Journal of Physics Condensed Matter Vol. 17(38), pp. 5971-5985	DOI
Abstract: The heat capacity (Cp) and dilatation (α) of YB 12 and LuB12 are studied. Cp of the zone-melted YB12 tricrystal is measured in the range 2.5-70 K, of the zone-melted LuB12 single crystal in the range 0.6-70 K, and of the LuB12 powder sample in the range 4.3-300 K; α of the zone-melted YB12 tricrystal and LuB12 single crystals is measured in the range 5-200 K. At low temperatures a negative thermal expansion (NTE) is revealed for both compounds: for YB12 at 50-70 K, for LuB12 at 10-20 K and 60-130 K. Their high-temperature NTE is a consequence of nearly non-interacting freely oscillating metal ions (Einstein oscillators) in cavities of a simple cubic rigid Debye lattice formed by B 12 cage units. The Einstein temperatures are ∼254 and ∼164 K, and the Debye temperatures are ∼1040 K and ∼1190 K for YB12 and LuB12 respectively. The LuB12 low-temperature NTE is connected with an induced low-energy defect mode. The YB12 superconducting transition has not been detected up to 2.5 K.
BibTeX: @article{Czopnik20055971, author = {Czopnik, A. and Shitsevalova, N. and Pluzhnikov, V. and Krivchikov, A. and Paderno, Y. and Onuki, Y.}, title = {Low-temperature thermal properties of yttrium and lutetium dodecaborides}, journal = {Journal of Physics Condensed Matter}, year = {2005}, volume = {17}, number = {38}, pages = {5971-5985}, doi = {http://dx.doi.org/10.1088/0953-8984/17/38/003} }
Fertman E., Sheptyakov D., Beznosov A., Desnenko V., Khalyavin D.	Magnetic states and the crystal volume of Nd2/3Ca 1/3MnO3: Analysis of phase transformations [Abstract] [BibTeX]	2005	Journal of Magnetism and Magnetic Materials Vol. 293(2), pp. 787-792	DOI
Abstract: The neutron diffraction and magnetic studies of the Nd2/3Ca 1/3MnO3 ceramic compound have been carried out aiming to reveal the signs of phase separation in the system. A well-expressed step in the inverse magnetic susceptibility of the system found at T∼212K was considered to be a result of the charge ordering. The elastic neutron scattering study upon heating has shown a diminishing to zero of intensities of the diffraction peaks, corresponding to the ferromagnetic B-type structure, antiferromagnetic DE-type and pseudo-CE-type structures at ∼70 and ∼80 K by the first order phase transitions, and at ∼130 K by the second order transition, respectively. We suppose that the set of the revealed magnetic structures relates to the set of structure regions formed due to the nucleation of the martensitic particles within the parent matrix below the charge ordering temperature.
BibTeX: @article{Fertman2005787, author = {Fertman, E. and Sheptyakov, D. and Beznosov, A. and Desnenko, V. and Khalyavin, D.}, title = {Magnetic states and the crystal volume of Nd2/3Ca 1/3MnO3: Analysis of phase transformations}, journal = {Journal of Magnetism and Magnetic Materials}, year = {2005}, volume = {293}, number = {2}, pages = {787-792}, doi = {http://dx.doi.org/10.1016/j.jmmm.2004.12.001} }
Fil V., Fil D., Avramenko Y., Gaiduk A., Johnson W.	Surface pinning in an amorphous ZrTiCuNiBe alloy [Abstract] [BibTeX]	2005	Physical Review B - Condensed Matter and Materials Physics Vol. 71(9), pp. 092504	DOI
Abstract: We have measured the amplitude and the phase of an electromagnetic (EM) field radiated from a superconductor (amorphous ZrTiCuNiBe alloy) in the mixed state due to the interaction of the flux lattice with an elastic wave. The results point to an essential contribution of a surface pinning into the flux lattice dynamics. We propose a model that describes radiation of the EM field from superconductors with nonuniform pinning. The model allows us to reconstruct the viscosity and the Labusch parameters from the experimental data. The behavior of the Labusch parameter can be qualitatively explained in terms of the collective pinning theory with the allowance of thermal fluctuations.
BibTeX: @article{Fil2005, author = {Fil, V.D. and Fil, D.V. and Avramenko, Yu.A. and Gaiduk, A.L. and Johnson, W.L.}, title = {Surface pinning in an amorphous ZrTiCuNiBe alloy}, journal = {Physical Review B - Condensed Matter and Materials Physics}, year = {2005}, volume = {71}, number = {9}, pages = {092504}, doi = {http://dx.doi.org/10.1103/PhysRevB.71.092504} }
Kumzerov Y., Parfen'eva L., Smirnov I., Krivchikov A., Zvyagina G., Fil' V., Misiorek H., Mucha J., Jezowski A.	Thermal and acoustic properties of chrysotile asbestos [Abstract] [BibTeX]	2005	Physics of the Solid State Vol. 47(2), pp. 370-373	DOI
Abstract: The thermal conductivity, specific heat, and sound velocity of crystalline chrysotile asbestos made up of hollow tubular fibrils of composition Mg"3Si"2O"5(OH)"4 have been measured at temperatures of 5-300, 3-65, and 77 K, respectively. An analysis is made of the experimental data obtained.
BibTeX: @article{Kumzerov2005370, author = {Kumzerov, Yu.A. and Parfen'eva, L.S. and Smirnov, I.A. and Krivchikov, A.I. and Zvyagina, G.A. and Fil', V.D. and Misiorek, H. and Mucha, J. and Jezowski, A.}, title = {Thermal and acoustic properties of chrysotile asbestos}, journal = {Physics of the Solid State}, year = {2005}, volume = {47}, number = {2}, pages = {370-373}, doi = {http://dx.doi.org/10.1134/1.1866422} }
Pluzhnikov V., Grechnev G., Czopnik A., Eriksson O.	Pressure effect on the Fermi surface and electronic structure of LuGa 3 and TmGa3 [Abstract] [BibTeX]	2005	Low Temperature Physics Vol. 31(3), pp. 313-320	DOI
Abstract: The Fermi surfaces and cyclotron masses of LuGa3 and TmGa 3 compounds are studied by means of the de Haas-van Alphen effect technique under pressure. Highly anisotropic pressure dependences of the de Haas-van Alphen frequencies and cyclotron masses are observed in both compounds. Concurrently, ab initio calculations of the volume-dependent band structures are been carried out for these compounds, including the ferromagnetic- configuration phase of TmGa3, by employing a relativistic version of the full-potential linear muffin-tin orbital method within the local spin-density approximation. The experimental data are analyzed on the basis of the calculated volume-dependent band structures and compared with the corresponding pressure effects in the isostructural compound ErGa3.
BibTeX: @article{Pluzhnikov2005313, author = {Pluzhnikov, V.B. and Grechnev, G.E. and Czopnik, A. and Eriksson, O.}, title = {Pressure effect on the Fermi surface and electronic structure of LuGa 3 and TmGa3}, journal = {Low Temperature Physics}, year = {2005}, volume = {31}, number = {3}, pages = {313-320}, doi = {http://dx.doi.org/10.1063/1.1884445} }
Zholobenko A., Mikitik G., Fil' V., Fil' D., Kim J., Choi E., Lee S.	Pinning in nomagnetic borocarbides [Abstract] [BibTeX]	2005	Low Temperature Physics Vol. 31(12), pp. 1043-1047	DOI
Abstract: The field dependences of the Labush parameter in nonmagnetic borocarbides are measured by a method that does not require achieving a critical state. The expected values of the critical current are estimated. The values obtained are two orders of magnitude greater than the results of "direct" measurements performed on the basis of transport (magnetic) experiments. A giant peak effect, which the collective pinning model describes quantitatively well, is observed in the field dependences of the Labush parameter in Y-containing borocarbides.
BibTeX: @article{Zholobenko20051043, author = {Zholobenko, A.N. and Mikitik, G.P. and Fil', V.D. and Fil', D.V. and Kim, J.D. and Choi, E.M. and Lee, S.I.}, title = {Pinning in nomagnetic borocarbides}, journal = {Low Temperature Physics}, year = {2005}, volume = {31}, number = {12}, pages = {1043-1047}, doi = {http://dx.doi.org/10.1063/1.2144457} }
Avramenko Y., Bezuglyi E., Burma N., Gokhfeld V., Kolobov I., Fil V., Shevchenko O.	Electric field accompanying a longitudinal wave in pure metal [Abstract] [BibTeX]	2004	Materials Science and Engineering A Vol. 370(1-2), pp. 373-375	DOI
Abstract: The temperature dependence of the amplitude and phase of the electric potential arising at a plane boundary of a metal when a longitudinal acoustic wave is incident normally on it is investigated theoretically and experimentally. The surface potential is formed by two contributions, one of which is spatially periodic; the second one is aperiodic and arises as a result of an additional nonuniformity of the electron distribution in a surface layer of the metal. The phases of these contributions are shifted by approximately π /2. In the normal state, the experiment is in qualitative agreement with the theory. The superconducting transition is accompanied by catastrophically rapid vanishing of the electric potential, in sharp contrast to the theoretical estimates.
BibTeX: @article{Avramenko2004373, author = {Avramenko, Yu.A. and Bezuglyi, E.V. and Burma, N.G. and Gokhfeld, V.M. and Kolobov, I.G. and Fil, V.D. and Shevchenko, O.A.}, title = {Electric field accompanying a longitudinal wave in pure metal}, journal = {Materials Science and Engineering A}, year = {2004}, volume = {370}, number = {1-2}, pages = {373-375}, doi = {http://dx.doi.org/10.1016/j.msea.2002.12.009} }
Baranovskiy A., Grechnev G., Panfilov A., Svechkarev I., Hackemer A., Solyga M., Czopnik A.	Pressure effects on magnetic properties and electronic structure of GdIn3-xSnx alloys [Abstract] [BibTeX]	2004	Czechoslovak Journal of Physics Vol. 54(SUPPL. 4), pp. D351-D354	DOI
Abstract: The magnetic susceptibility χ of antiferromagnetic GdIn 3-xSnx alloys (0 ≤ x ≤ 3) is studied under hydrostatic pressure up to 2 kbar at fixed temperatures (78 and 300K) above TN, along with the χ(T) dependence in the range 2-400 K. This study revealed well defined peculiarities in the concentration dependences TN(x), the paramagnetic Curie temperature Θ (x), as well as the pressure effect dlnχ(x)/dP. The experimental estimates of the volume derivative dlnΘ/dlnV and results of ab initio calculations of the volume-dependent electronic structure of alloys were used to analyze the nature of f-f interactions in the GdIn3-xSnx system.
BibTeX: @article{Baranovskiy2004, author = {Baranovskiy, A.E. and Grechnev, G.E. and Panfilov, A.S. and Svechkarev, I.V. and Hackemer, A. and Solyga, M. and Czopnik, A.}, title = {Pressure effects on magnetic properties and electronic structure of GdIn3-xSnx alloys}, journal = {Czechoslovak Journal of Physics}, year = {2004}, volume = {54}, number = {SUPPL. 4}, pages = {D351-D354}, doi = {http://dx.doi.org/10.1007/s10582-004-0099-y} }
Baranovskiy A., Grechnev G., Svechkarev I., Czopnik A.	Peculiarites of diamagnetic susceptibility in RM3 compounds and alloys [Abstract] [BibTeX]	2004	Czechoslovak Journal of Physics Vol. 54(SUPPL. 4), pp. D355-D358	DOI
Abstract: Pronounced singularities of orbital magnetic susceptibility, χ, are demonstrated experimentally and theoretically for RM3 alloys and compounds. The degeneracy points of the electronic energy bands close to the Fermi level are found to be responsible for the anomalous diamagnetism in YbSn3, YbPb3, CaSn3, and LaIn 3-xSnx alloys. The appearance and smearing of these anomalies with temperature and impurities are analyzed, and corresponding band structure and scattering parameters are determined.
BibTeX: @article{Baranovskiy2004a, author = {Baranovskiy, A.E. and Grechnev, G.E. and Svechkarev, I.V. and Czopnik, A.}, title = {Peculiarites of diamagnetic susceptibility in RM3 compounds and alloys}, journal = {Czechoslovak Journal of Physics}, year = {2004}, volume = {54}, number = {SUPPL. 4}, pages = {D355-D358}, doi = {http://dx.doi.org/10.1007/s10582-004-0100-9} }
Belevtsev B., Dalakova N., Savitsky V., Panfilov A., Braude I., Bondarenko A.	Magnetoresistive study of the antiferromagnetic-weak ferromagnetic transition in single-crystal La2CuO4+δ [Abstract] [BibTeX]	2004	Low Temperature Physics Vol. 30(5), pp. 411-416	DOI
Abstract: Resistive measurements were made to study the magnetic field-induced antiferromagnetic (AF) - weak ferromagnetic (WF) transition in the La 2CuO4 single crystal. The magnetic field (dc or pulsed) was applied normally to the CuO2 layers. The transition manifested itself in a drastic decrease of the resistance in critical fields of 5-7 T. The study is the first to display the effect of the AF-WF transition on the conductivity of the La2CuO4 single crystal in the direction parallel to the CuO2 layers. The results provide support for the three-dimensional nature of the hopping conduction of this layered oxide.
BibTeX: @article{Belevtsev2004411, author = {Belevtsev, B.I. and Dalakova, N.V. and Savitsky, V.N. and Panfilov, A.S. and Braude, I.S. and Bondarenko, A.V.}, title = {Magnetoresistive study of the antiferromagnetic-weak ferromagnetic transition in single-crystal La2CuO4+δ}, journal = {Low Temperature Physics}, year = {2004}, volume = {30}, number = {5}, pages = {411-416}, doi = {http://dx.doi.org/10.1063/1.1739162} }
Belevtsev B., Dalakova N., Savitskij V., Bondarenko A., Panfilov A., Braude I.	Study of magnetic field-induced antiferromagnetic-weak ferromagnetic transition in La2CuO4 single crystal by resistive measurement [BibTeX]	2004	Izvestiya Akademii Nauk. Ser. Fizicheskaya Vol. 68(5), pp. 678-681	URL
BibTeX: @article{Belevtsev2004678, author = {Belevtsev, B.I. and Dalakova, N.V. and Savitskij, V.N. and Bondarenko, A.V. and Panfilov, A.S. and Braude, I.S.}, title = {Study of magnetic field-induced antiferromagnetic-weak ferromagnetic transition in La2CuO4 single crystal by resistive measurement}, journal = {Izvestiya Akademii Nauk. Ser. Fizicheskaya}, year = {2004}, volume = {68}, number = {5}, pages = {678-681}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-2942648950&partnerID=40&md5=2b81538a4a0003b6fcb6abc0b32fc740} }
Belevtsev B., Kirichenko A., Cherpak N., Golubnichaya G., Maximchuk I., Beliayev E., Panfilov A., Fink-Finowicki J.	Giant magnetic-field changes in radio-frequency absorption in La 0.67Sr0.33MnO3 near the Curie temperature [Abstract] [BibTeX]	2004	Journal of Magnetism and Magnetic Materials Vol. 281(1), pp. 97-104	DOI
Abstract: The DC transport properties of and the radio-frequency (RF) wave absorption (at 2.525 MHz) in a sample of La0.67Sr0.33MnO3 prepared by floating-zone method are measured. The Curie temperature, T c, of the sample is about 374 K. Giant temperature and magnetic-field variations in RF absorption are found in the vicinity of Tc. Relative change of the RF absorption in magnetic field (magnetoabsorption) is about 67% in field 2.1 kOe and about 55% in field 1 kOe. This giant magnetoabsorption effect can be used to develop RF devices controlled by temperature and low magnetic field. A weak temperature dependence of magnetoabsorption for the sample studied in the range from room temperature to about 350 K makes it especially attractive for practical use. The RF study supplemented with transport, magnetoresistive and magnetic measurements enables us to discuss the optimal properties of manganite samples for observation of giant magnetoabsorption in low field.
BibTeX: @article{Belevtsev200497, author = {Belevtsev, B.I. and Kirichenko, A.Ya. and Cherpak, N.T. and Golubnichaya, G.V. and Maximchuk, I.G. and Beliayev, E.Yu. and Panfilov, A.S. and Fink-Finowicki, J.}, title = {Giant magnetic-field changes in radio-frequency absorption in La 0.67Sr0.33MnO3 near the Curie temperature}, journal = {Journal of Magnetism and Magnetic Materials}, year = {2004}, volume = {281}, number = {1}, pages = {97-104}, doi = {http://dx.doi.org/10.1016/j.jmmm.2004.04.094} }
Burma N., Petrishin A., Ryabukha N., Fil' V.	Anomalous acoustic transparency under conditions of the tilt effect [Abstract] [BibTeX]	2004	Low Temperature Physics Vol. 30(2), pp. 149-152	DOI
Abstract: An anomalous acoustic transparency phenomenon is discovered and investigated in high-purity Ga samples under conditions of the tilt effect. This phenomenon is due to resonance coupling of the high-frequency elastic waves with weakly damped electromagnetic eigenmodes of the metal.
BibTeX: @article{Burma2004149, author = {Burma, N.G. and Petrishin, A.I. and Ryabukha, N.A. and Fil', V.D.}, title = {Anomalous acoustic transparency under conditions of the tilt effect}, journal = {Low Temperature Physics}, year = {2004}, volume = {30}, number = {2}, pages = {149-152}, doi = {http://dx.doi.org/10.1063/1.1645167} }
Czopnik A., Shitsevalova N., Krivchikov A., Pluzhnikov V., Paderno Y., Onuki Y.	Thermal properties of rare earth dodecaborides [Abstract] [BibTeX]	2004	Journal of Solid State Chemistry Vol. 177(2), pp. 507-514	DOI
Abstract: We have measured heat capacity and thermal expansion of rare earth dodecaborides REB12 (RE=Y, Tb-Tm, Lu). YB12 and LuB 12 are diamagnetics whereas the other dodecaborides are ordered antiferromagnetically. The amplitude of the heat capacity discontinuity at the Néel temperature and the shape of the heat capacity variation in the critical region for all these antiferromagnetics are characteristics for amplitude-modulated magnetic structures. In the ordered state TbB12 reveals two first-order phase transitions, most likely due to magnetic structure changes. The heat capacity of ErB12 just below the Néel point shows an anomaly of unclear origin. From the Schottky contribution to the heat capacity we have determined crystal field parameters. They are completely different than that is estimated from Point Charge Model.
BibTeX: @article{Czopnik2004507, author = {Czopnik, A. and Shitsevalova, N. and Krivchikov, A. and Pluzhnikov, V. and Paderno, Y. and Onuki, Y.}, title = {Thermal properties of rare earth dodecaborides}, journal = {Journal of Solid State Chemistry}, publisher = {Academic Press Inc.}, year = {2004}, volume = {177}, number = {2}, pages = {507-514}, doi = {http://dx.doi.org/10.1016/j.jssc.2003.04.003} }
Desnenko V., Dolya S., Isaev N., Svechkarev I., Fedorchenko A.	Anomalous diamagnetism in aluminum-lithium alloys [Abstract] [BibTeX]	2004	Low Temperature Physics Vol. 30(5), pp. 425-427	DOI
Abstract: In the region of the equilibrium solid solutions of lithium in aluminum an anomalous low-temperature peak of diamagnetism is observed which is due to the presence of a boundary point on a line of band degeneracy directly below the Fermi level. The position and structure of the peak in the average valence function are analogous to those studied previously in the aging systems Al-Mg and Al-Zn under suitable heat treatment. The value of the lithium impurity scattering parameter for the electron states in the vicinity of the point of degeneracy mentioned is estimated, and the linear relation of that parameter with impurity-related electrical resistance in aluminum alloys is established.
BibTeX: @article{Desnenko2004425, author = {Desnenko, V.A. and Dolya, S.N. and Isaev, N.V. and Svechkarev, I.V. and Fedorchenko, A.V.}, title = {Anomalous diamagnetism in aluminum-lithium alloys}, journal = {Low Temperature Physics}, year = {2004}, volume = {30}, number = {5}, pages = {425-427}, doi = {http://dx.doi.org/10.1063/1.1739165} }
Fertman E., Sheptyakov D., Beznosov A., Desnenko V., Khalyavin D.	Exchange interactions and magnetic subsystems in Nd2/3Ca 1/3MnO3: Analysis of temperature effects [Abstract] [BibTeX]	2004	Physica B: Condensed Matter Vol. 350(1-3 SUPPL. 1), pp. e9-e12	DOI
Abstract: Two antiferromagnetic substructures of the pseudo-CE type are revealed by neutron-diffraction studies. Their propagation vectors are k1 = (0,0,1/2) and k2 = (1/2,0,1/2) in the Pnma crystal-structure unit cell. The intensities of the magnetic Bragg peaks are proportional to the squares of a modified Brillouin function for spin \|. Its molecular field parameters depend on the reduced sublattice magnetizations σ as T N(1-eσ2). The fitting parameters are the Néel temperatures TN1 = 120 and TN2 = 123 K, and e1 = 0.2, e2 = 0.16 showing a weakening of the effective exchange. Below 27 K, an additional increase of the magnetic peak intensities is observed. Below ∼ 85K, the magnetic behavior is characteristic for a cluster glass. The uniaxial pressure effect on the DC-magnetization shows a sharp minimum near 120 K and it changes sign near 85 K, implying an alteration of the effective superexchange integral.
BibTeX: @article{Fertman2004, author = {Fertman, E. and Sheptyakov, D. and Beznosov, A. and Desnenko, V. and Khalyavin, D.}, title = {Exchange interactions and magnetic subsystems in Nd2/3Ca 1/3MnO3: Analysis of temperature effects}, journal = {Physica B: Condensed Matter}, year = {2004}, volume = {350}, number = {1-3 SUPPL. 1}, pages = {e9-e12}, doi = {http://dx.doi.org/10.1016/j.physb.2004.03.003} }
Fertman E., Ritter C., Beznosov A., Desnenko V., Khalyavin D.	Crystallographic phases in La2/3Ba1/3MnO3: Temperature transformations and relation to magnetism [Abstract] [BibTeX]	2004	Physica B: Condensed Matter Vol. 350(4), pp. 227-230	DOI
Abstract: The structural and magnetic analysis of polycrystalline samples of La 2/3Ba1/3MnO3 has been carried out between 5 and 370K by means of neutron-diffraction technique and DC magnetic measurements. Below the Curie point TC=314K the system undergoes a structural phase transition R3̄c-Imma. The transition extends over a wide temperature range, proceeds most rapidly in the vicinity of Tm=200K, and has characteristic features of a martensitic phase transition. The uniaxial pressure effect on the DC magnetization is maximal at 200K. Two magnetic phase transitions (of the second order at 250K and of the First order at 177.5K) are reflected mainly in the R3̄c phase crystal parameters.
BibTeX: @article{Fertman2004227, author = {Fertman, E. and Ritter, C. and Beznosov, A. and Desnenko, V. and Khalyavin, D.}, title = {Crystallographic phases in La2/3Ba1/3MnO3: Temperature transformations and relation to magnetism}, journal = {Physica B: Condensed Matter}, year = {2004}, volume = {350}, number = {4}, pages = {227-230}, doi = {http://dx.doi.org/10.1016/j.physb.2004.04.034} }
Fil V., Knigavko A., Zholobenko A., Choi E.-M., Lee S.-I.	Elastic anomalies in HoNi2B2C single crystals [Abstract] [BibTeX]	2004	Physical Review B - Condensed Matter and Materials Physics Vol. 70(22), pp. 220504-1-220504-4	DOI
Abstract: We have measured temperature and magnetic field dependencies of the sound velocities and the sound attenuation in HoNi2B2C single crystals. The main result is a huge softening of the velocity of C66 mode due to a cooperative Jahn-Teller effect, resulting in a tetragonal-orthorhombic structural phase transition. Anomalies in the behavior of the C66 mode through various magnetic phase transitions permit us to revise the low temperature H-T phase diagrams of this compound.
BibTeX: @article{Fil2004, author = {Fil, V.D. and Knigavko, A. and Zholobenko, A.N. and Choi, E.-M. and Lee, S.-I.}, title = {Elastic anomalies in HoNi2B2C single crystals}, journal = {Physical Review B - Condensed Matter and Materials Physics}, year = {2004}, volume = {70}, number = {22}, pages = {220504-1-220504-4}, doi = {http://dx.doi.org/10.1103/PhysRevB.70.220504} }
Grechnev G., Panfilov A., Svechkarev I., Czopnik A., Hackemer A., Kaczorowski D., Eriksson O.	Pressure effect on magnetic properties of UX3 (X=Al, Ga, In, Si, Ge) compounds [Abstract] [BibTeX]	2004	Czechoslovak Journal of Physics Vol. 54(SUPPL. 4), pp. D359-D362	DOI
Abstract: Magnetic susceptibility χ of UX3 compounds (X=Al, Ga, In, Si, Ge) is studied under pressure up to 2 kbar at some fixed temperatures in the range 78-300 K by a modified Faraday method. A pronounced pressure effect on χ has been revealed, and the magnetovolume derivatives, dlnχ/dlnV, are found to be temperature independent, except for UAl3 and UIn 3. A pressure effect on the Néel temperature TN was also detected in antiferromagnetic UGa3 and UIn3. The electronic structures of the UX3 compounds were calculated by employing a relativistic full-potential LMTO method. The evaluated χ and magnetic moments in UX3 and their volume derivatives are in agreement with experimental data.
BibTeX: @article{Grechnev2004, author = {Grechnev, G.E. and Panfilov, A.S. and Svechkarev, I.V. and Czopnik, A. and Hackemer, A. and Kaczorowski, D. and Eriksson, O.}, title = {Pressure effect on magnetic properties of UX3 (X=Al, Ga, In, Si, Ge) compounds}, journal = {Czechoslovak Journal of Physics}, year = {2004}, volume = {54}, number = {SUPPL. 4}, pages = {D359-D362}, doi = {http://dx.doi.org/10.1007/s10582-004-0101-8} }
Grechnev G., Ahuja R., Guo J., Eriksson O.	Electronic structure and optical spectra of novel rechargeable lithium batteries [Abstract] [BibTeX]	2004	Proceedings of SPIE - The International Society for Optical Engineering Vol. 5507, pp. 35-44	DOI
Abstract: Electronic spectra of promising materials for rechargeable lithium batteries, LiC6 and LiMn2O4, have been studied. Theoretical calculations in combination with experiments for the π* and σ* x-ray absorption edges are reported for the pure graphite and the graphite intercalation compound, LiC6. The anisotropy of the absorption spectra is due to the difference in the optical matrix elements for two different polarizations, which is a result of the anisotropic crystallographic and electronic properties of LiC6. Theory and experiment agree well for the π* and σ* resonances. By comparing calculations which include the effect of the core hole with similar calculations which do not, we conclude that 1s x-ray absorption in LiC 6 is partly associated with an excitonic effect. The electronic structure and optical absorption spectrum of LiMn2O4 spinel has been calculated and compared with available experimental data. The calculated absorption coefficient appeared to be in agreement with experiment, and the features of the absorption are associated with transitions between the exchange and crystal-field split t2g and eg d-bands of manganese in LiMn2O4 spinel.
BibTeX: @conference{Grechnev200435, author = {Grechnev, G.E. and Ahuja, R. and Guo, J. and Eriksson, O.}, title = {Electronic structure and optical spectra of novel rechargeable lithium batteries}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2004}, volume = {5507}, pages = {35-44}, doi = {http://dx.doi.org/10.1117/12.569601} }
Grechnev G.	Electronic structure and magnetic properties of LiM2O4 spinels [BibTeX]	2004	Izvestiya Akademii Nauk. Ser. Fizicheskaya Vol. 68(5), pp. 671-674	URL
BibTeX: @article{Grechnev2004671, author = {Grechnev, G.E.}, title = {Electronic structure and magnetic properties of LiM2O4 spinels}, journal = {Izvestiya Akademii Nauk. Ser. Fizicheskaya}, year = {2004}, volume = {68}, number = {5}, pages = {671-674}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-2942685875&partnerID=40&md5=d09b2160ea587f81a9f8d81efafcb787} }
Zvyagina G., Fil' V., Kharchenko Y., Nesterenko N.	Phase transitions in the magnetoelastic crystals CsDy1-xGd x(MoO4)2 [Abstract] [BibTeX]	2004	Low Temperature Physics Vol. 30(3), pp. 236-246	DOI
Abstract: Based on the data of ultrasonic studies and on the temperature behavior of the absorption spectra, a study of the phase diagram of the crystals CsDy 1-xGdx(MoO4)2 is made and the structural distortions occurring as a result of the pseudo-Jahn-Teller effect are discussed. It is shown that in the presence of impurities there are several lines of phase transitions on the x-T phase diagram. It is established that one of the phase transitions these found is essentially of a magnetoelastic origin.
BibTeX: @article{Zvyagina2004236, author = {Zvyagina, G.A. and Fil', V.D. and Kharchenko, Yu.N. and Nesterenko, N.M.}, title = {Phase transitions in the magnetoelastic crystals CsDy1-xGd x(MoO4)2}, journal = {Low Temperature Physics}, year = {2004}, volume = {30}, number = {3}, pages = {236-246}, doi = {http://dx.doi.org/10.1063/1.1645185} }
Baranovskiy A., Grechnev G., Mikitik G., Svechakarev I.	Anomalous diamagnetism in the intermetallic compounds CaPb3 and YbPb3 [Abstract] [BibTeX]	2003	Low Temperature Physics Vol. 29(4), pp. 356-358	DOI
Abstract: A theoretical study is made of the features of the band structure and orbital magnetic susceptibility χ of the intermetallic compounds CaPb 3 and YbPb3. It is shown that the anomalous, strongly temperature-dependent diamagnetism observed earlier in experiments on these compounds is of an interband origin and is due to the presence of degenerate electronic states in the immediate vicinity of the Fermi level. The characteristics of the degenerate states for the two compounds are determined by reconciling the calculated χ(T) dependence with experiment in the temperature range 5K≤T≤300K.
BibTeX: @article{Baranovskiy2003356, author = {Baranovskiy, A.E. and Grechnev, G.E. and Mikitik, G.P. and Svechakarev, I.V.}, title = {Anomalous diamagnetism in the intermetallic compounds CaPb3 and YbPb3}, journal = {Low Temperature Physics}, year = {2003}, volume = {29}, number = {4}, pages = {356-358}, doi = {http://dx.doi.org/10.1063/1.1572412} }
Baranovskiy A., Grechnev G., Svechkarev I., Eriksson O.	Electronic structure and magnetic properties of GdM2 compounds [Abstract] [BibTeX]	2003	Journal of Magnetism and Magnetic Materials Vol. 258-259, pp. 520-522	DOI
Abstract: Electronic structure calculations are carried out for the ferromagnetic GdM2 compounds (M = Mg, Al, Fe, Co, Ni, Rh, Ir, Pt). By using the calculated susceptibilities, densities of electronic states, and exchange parameters, the Curie temperatures were evaluated for these compounds in the framework of a modified molecular-field approach. The calculated magnetic ordering temperatures appeared to be in improved agreement with experimental data, in contrast to the results obtained within a conventional mean-field theory.
BibTeX: @article{Baranovskiy2003520, author = {Baranovskiy, A.E. and Grechnev, G.E. and Svechkarev, I.V. and Eriksson, O.}, title = {Electronic structure and magnetic properties of GdM2 compounds}, journal = {Journal of Magnetism and Magnetic Materials}, year = {2003}, volume = {258-259}, pages = {520-522}, doi = {http://dx.doi.org/10.1016/S0304-8853(02)01131-9} }
Belevtsev B., Krasovitsky V., Panfilov A., Chukanova I.	Magnetoresistance and magnetic anisotropy in La0.5Sr0.5CoO3-δ film [Abstract] [BibTeX]	2003	Journal of Magnetism and Magnetic Materials Vol. 258-259, pp. 280-282	DOI
Abstract: The magnetic and transport properties of La0.5Sr0.5CoO3-δ film grown on a LaAlO3 substrate by pulsed-laser deposition are studied. The properties are found to be influenced by a combined influence of the magnetic anisotropy and inhomogeneity. Magnetoresistance anisotropy is determined by the shape anisotropy and the strain-induced magnetic anisotropy due to the film-substrate lattice interaction. Indications of the temperature-driven spin-reorientation transition from an out-of-plane orderded state at low temperatures to an in-plane ordered state at high temperatures as a result of competition between the mentioned anisotropy sources are found.
BibTeX: @article{Belevtsev2003280, author = {Belevtsev, B.I. and Krasovitsky, V.B. and Panfilov, A.S. and Chukanova, I.N.}, title = {Magnetoresistance and magnetic anisotropy in La0.5Sr0.5CoO3-δ film}, journal = {Journal of Magnetism and Magnetic Materials}, year = {2003}, volume = {258-259}, pages = {280-282}, doi = {http://dx.doi.org/10.1016/S0304-8853(02)01095-8} }
Belevtsev B., Dalakova N., Panfilov A., Braude I., Bondarenko A.	Anisotropy of the hopping magnetoresistance of antiferromagnetic La2CuO4+δ single crystals [Abstract] [BibTeX]	2003	Low Temperature Physics Vol. 29(4), pp. 300-304	DOI
Abstract: The anisotropy of the hopping conductivity of antiferromagnetic La 2CuO4+δ single crystals with TN≈188K is investigated in the temperature range 5-295 K and the anisotropy of their magnetoresistance, in the temperature range 5-55 K. The resistance is measured by the Montgomery method for different combinations of directions of the transport current and magnetic field relative to the crystallographic axes. For the case when the field and transport current are directed parallel to the CuO2 layers, a transition from negative to positive magnetoresistance is observed when the temperature is raised to T≈20K. For fields perpendicular to the CuO2 layers, only negative magnetoresistance is observed. The nature of the positive magnetoresistance is discussed. It is shown that the effect is most likely due not to the interaction of the spin of the charge carriers with the surrounding magnetic medium but to the orbital motion of these carriers. The corresponding values of the positive magnetoresistance and its behavior as a function of magnetic field and temperature are found using the well-known model of Shklovskii and Efros, which is based on taking into account the compression of the impurity wave functions of the charge carriers in the magnetic field.
BibTeX: @article{Belevtsev2003300, author = {Belevtsev, B.I. and Dalakova, N.V. and Panfilov, A.S. and Braude, I.S. and Bondarenko, A.V.}, title = {Anisotropy of the hopping magnetoresistance of antiferromagnetic La2CuO4+δ single crystals}, journal = {Low Temperature Physics}, year = {2003}, volume = {29}, number = {4}, pages = {300-304}, doi = {http://dx.doi.org/10.1063/1.1542472} }
Belevtsev B., Krasovitsky V., Panfilov A., Chukanova I.	Anisotropic magnetoresistive and magnetic properties of La0.5Sr0.5CoO3-δ film [Abstract] [BibTeX]	2003	Low Temperature Physics Vol. 29(7), pp. 566-570	DOI
Abstract: The magnetic and transport properties of a La0.5Sr 0.5CoO3-δ film grown on a LaAlO3 substrate by pulsed-laser deposition are studied. The properties are found to be influenced by the magnetic anisotropy and inhomogeneity. Magnetoresistance anisotropy is determined by the shape anisotropy of the magnetization and the strain-induced magnetic anisotropy due to the film-substrate lattice interaction. Indications of the temperature-driven spin reorientation transition from an out-of-plane ordered state at low temperatures to an in-plane ordered state at high temperatures as a result of competition between the aforementioned sources of magnetic anisotropy are found.
BibTeX: @article{Belevtsev2003566, author = {Belevtsev, B.I. and Krasovitsky, V.B. and Panfilov, A.S. and Chukanova, I.N.}, title = {Anisotropic magnetoresistive and magnetic properties of La0.5Sr0.5CoO3-δ film}, journal = {Low Temperature Physics}, year = {2003}, volume = {29}, number = {7}, pages = {566-570}, doi = {http://dx.doi.org/10.1063/1.1596581} }
Gospodarev I., Eremenko A., Ignatova T., Kamarchuk G., Kolobov I., Minaev P., Syrkin E., Feodosyev S., Fil V., Soreau-Leblanc A., Molinie P., Faulques E.	Elastic properties and phonon spectra of quasi-two-dimensional VSe2 [Abstract] [BibTeX]	2003	Low Temperature Physics Vol. 29(2), pp. 151-154	DOI
Abstract: A recently developed method is used to make acoustic measurements of VSe2 single crystals. The components of the elastic constant tensor are determined from the data of these measurements. The experimental data are used to calculate the total and partial phonon densities of VSe2, which permit an explanation of the vibrational spectra of this compound.
BibTeX: @article{Gospodarev2003151, author = {Gospodarev, I.A. and Eremenko, A.V. and Ignatova, T.V. and Kamarchuk, G.V. and Kolobov, I.G. and Minaev, P.A. and Syrkin, E.S. and Feodosyev, S.B. and Fil, V.D. and Soreau-Leblanc, A. and Molinie, P. and Faulques, E.C.}, title = {Elastic properties and phonon spectra of quasi-two-dimensional VSe2}, journal = {Low Temperature Physics}, year = {2003}, volume = {29}, number = {2}, pages = {151-154}, doi = {http://dx.doi.org/10.1063/1.1542414} }
Grechnev G., Ahuja R., Johansson B., Eriksson O.	Electronic structure and magnetic properties of lithium manganese spinels [Abstract] [BibTeX]	2003	Journal of Magnetism and Magnetic Materials Vol. 258-259, pp. 287-289	DOI
Abstract: The electronic and magnetic structures of the spinel-type lithium-manganese oxides were studied. The effect of the orthorhombic distortion on electronic structure and magnetism of LiMn2O4 was discussed. Manganese oxides were considered as strongly correlated systems, which could not be treated appropriately by the density functional theory (DFT).
BibTeX: @article{Grechnev2003287, author = {Grechnev, G.E. and Ahuja, R. and Johansson, B. and Eriksson, O.}, title = {Electronic structure and magnetic properties of lithium manganese spinels}, journal = {Journal of Magnetism and Magnetic Materials}, year = {2003}, volume = {258-259}, pages = {287-289}, doi = {http://dx.doi.org/10.1016/S0304-8853(02)01106-X} }
Grechnev G., Ahuja R., Eriksson O.	Magnetic susceptibility of hcp iron and the seismic anisotropy of Earth's inner core [Abstract] [BibTeX]	2003	Physical Review B - Condensed Matter and Materials Physics Vol. 68(6), pp. 644141-644148	DOI
Abstract: The seismic anisotropy of the Earth's core is believed to be due to a preferred orientation of hexagonal close packed (hcp) iron crystals that constitute the dominating element in the inner core. In this connection, the magnetic properties of the hcp iron in an external magnetic field are very interesting and are studied here by employing an ab initio full-potential linear muffin tin orbital method. By this means the magnetic susceptibility Χ of hcp iron and its anisotropy energy for pressures and temperatures corresponding to the Earth's inner core conditions have been evaluated in the framework of the local spin density approximation. The accuracy of this method has been validated by calculating the anisotropic susceptibility of paramagnetic transition metals that form in the hcp crystal structure at ambient conditions. Our calculations demonstrate that for hcp iron the anisotropy of Χ is dependent on the c/a ratio. In conjunction with recent data on the c/a ratio and elastic constants of hcp iron, the magnetic anisotropy can explain the seismic anisotropy of the Earth's inner core.
BibTeX: @article{Grechnev2003644141, author = {Grechnev, G.E. and Ahuja, R. and Eriksson, O.}, title = {Magnetic susceptibility of hcp iron and the seismic anisotropy of Earth's inner core}, journal = {Physical Review B - Condensed Matter and Materials Physics}, year = {2003}, volume = {68}, number = {6}, pages = {644141-644148}, doi = {http://dx.doi.org/10.1103/PhysRevB.68.064414} }
Masalitin E., Fil' V., Zhekov K., Zholobenko A., Ignatova T., Lee S.-I.	Elastic constants of borocarbides. New approach to acoustic measurement technique [Abstract] [BibTeX]	2003	Low Temperature Physics Vol. 29(1), pp. 72-76	DOI
Abstract: A new version of the phase method of determining the sound velocity is proposed and implemented. It utilizes the "Nonius" measurement technique and can give acceptable accuracy (≤1%) in samples of submillimeter size. Measurements of the sound velocity are made in single-crystal samples of the borocarbides RNi2B2C (R=Y, Lu, Ho). The elastic constants and the Debye temperature are calculated.
BibTeX: @article{Masalitin200372, author = {Masalitin, E.A. and Fil', V.D. and Zhekov, K.R. and Zholobenko, A.N. and Ignatova, T.V. and Lee, S.-I.}, title = {Elastic constants of borocarbides. New approach to acoustic measurement technique}, journal = {Low Temperature Physics}, year = {2003}, volume = {29}, number = {1}, pages = {72-76}, doi = {http://dx.doi.org/10.1063/1.1542380} }
Beznosov A.B., Desnenko V.A., Fertman E.L., Ritter C., Khalyavin D.D.	Magnetic and neutron diffraction study of La_2/3Ba_1/3MnO₃ perovskite manganite [Abstract] [BibTeX]	2003	Physical Review B - Condensed Matter and Materials Physics Vol. 68, pp. 054109	DOI
Abstract: The evolution of the magnetic and structural properties of La2/3Ba1/3MnO3 perovskite manganite was studied as a function of temperature by means of dc magnetic measurements at zero pressure as well as under uniaxial pressure of 0.1 kbar and neutron-diffraction between 5–370 K. It was revealed that below the Curie point TC=314 K in addition to the main crystallographic phase possessing a rhombohedral structure R¯3c some amount of the orthorhombic Imma phase appears in the system. The system undergoes three magnetic phase transitions in low magnetic fields (of the second order at 300 and 250 K and of the first order at 177.5 K) and passes via a sharp but not complete structural transition R¯3c↔Imma in the vicinity of Te=200 K. The reduced change of magnetic susceptibility delta_X/X under uniaxial pressure displays a sharp minimum at temperature Te. Below the Curie temperature from 300 to 250 K the magnetic susceptibility X is independent of the temperature, which is considered as an indication of a probable formation below Th=300 K of a long period magnetic structure (probably a sort of low-angle helix).
BibTeX: @article{beznosov2003, author = {Beznosov, A. B. and Desnenko, V. A. and Fertman, E. L. and Ritter, C. and Khalyavin, D. D.}, title = {Magnetic and neutron diffraction study of La_2/3Ba_1/3MnO₃ perovskite manganite}, journal = {Physical Review B - Condensed Matter and Materials Physics}, publisher = {American Physical Society}, year = {2003}, volume = {68}, pages = {054109}, doi = {http://dx.doi.org/10.1103/PhysRevB.68.054109} }
Avramenko Y., Bezuglyi E., Burma N., Kolobov I., Fil V., Shevchenko O., Gokhfeld V.	Characteristics of the electric field accompanying a longitudinal acoustic wave in a metal. Anomaly in the superconducting phase [Abstract] [BibTeX]	2002	Low Temperature Physics Vol. 28(5), pp. 328-336	DOI
Abstract: The temperature dependence of the amplitude and phase of the electric potential arising at a plane boundary of a conductor when a longitudinal acoustic wave is incident normally on it is investigated theoretically and experimentally. The surface potential is formed by two contributions, one of which is spatially periodic inside the sample, with the period of the acoustic field; the second is aperiodic and arises as a result of an additional nonuniformity of the electron distribution in a surface layer of the metal. In the nonlocal of parameters region the second contribution is dominant. The phases of these contributions are shifted by approximately π/2. For metals found in the normal state the experiment is in qualitative agreement with the theory. The superconducting transition is accompanied by catastrophically rapid vanishing of the electric potential, in sharp contrast to the theoretical estimates, which predict behavior similar to the BCS dependence of the attenuation coefficient for longitudinal sound.
BibTeX: @article{Avramenko2002328, author = {Avramenko, Yu.A. and Bezuglyi, E.V. and Burma, N.G. and Kolobov, I.G. and Fil, V.D. and Shevchenko, O.A. and Gokhfeld, V.M.}, title = {Characteristics of the electric field accompanying a longitudinal acoustic wave in a metal. Anomaly in the superconducting phase}, journal = {Low Temperature Physics}, year = {2002}, volume = {28}, number = {5}, pages = {328-336}, doi = {http://dx.doi.org/10.1063/1.1480239} }
Beznosov A., Belevtsev B., Fertman E., Desnenko V., Naugle D., Rathnayaka K., Parasiris A.	Exchange interaction and magnetoresistance in La2/3Ca 1/3MnO3: Experiment and models [Abstract] [BibTeX]	2002	Low Temperature Physics Vol. 28(7), pp. 556-561	DOI
Abstract: The magnetization M(T) and electrical resistivity ρ(T) of a La 2/3Ca1/3MnO3 film have been studied in the temperature range 5K≤T≤320K in the magnetic field intervals 10Oe≤H≤400Oe and 0≤H≤50kOe, respectively. It is found that the M(T)/M(0) value is larger than that predicted by the conventional molecular field model below the Curie point T=267K, and that the lnρ(T) dependence is close to linear in the temperature range 80K<T<200K (accordingly, ∂lnρ/∂T is constant in this region). A model of the electrical conductivity and magnetoresistivity of the system describing qualitatively the experimental results is proposed (the Δmτ model). The model includes a thermally activated (with characteristic energy Δ) mechanism of conductivity, dependence of the concentration and the effective mass (m) of the itinerant charge carriers on the magnetization, as well as scattering (with characteristic time τ) of the charge carriers by static breakings of the translational symmetry, thermal fluctuations of the magnetic order, and phonons.
BibTeX: @article{Beznosov2002556, author = {Beznosov, A.B. and Belevtsev, B.I. and Fertman, E.L. and Desnenko, V.A. and Naugle, D.G. and Rathnayaka, K.D.D. and Parasiris, A.}, title = {Exchange interaction and magnetoresistance in La2/3Ca 1/3MnO3: Experiment and models}, journal = {Low Temperature Physics}, year = {2002}, volume = {28}, number = {7}, pages = {556-561}, doi = {http://dx.doi.org/10.1063/1.1496667} }
Beznosov A., Desnenko V., Fertman E., Khalyavin D.	Uniaxial pressure effect on magnetic susceptibility of perovskite manganite La0.66Ba0.34MnO3 [Abstract] [BibTeX]	2002	Journal of Magnetism and Magnetic Materials Vol. 241(1), pp. 69-72	DOI
Abstract: Magnetization of La0.66Ba0.34MnO3 and its temperature behavior under a uniaxial pressure of 0.1 kbar are measured between 5 and 270 K in magnetic fields 0<H< 120 Oe. The magnetization represents nearly linear dependence on an external magnetic field. Temperature dependence of the magnetic susceptibility found represents a plateau, that is considered as an evidence of the formation of a long period magnetic structure (probably a sort of helix) below the Curie point. Pressure derivative of magnetization displays a sharp minimum at 200 K, pointing to an instability of electronic structure of the compound near this temperature.
BibTeX: @article{Beznosov200269, author = {Beznosov, A.B. and Desnenko, V.A. and Fertman, E.L. and Khalyavin, D.D.}, title = {Uniaxial pressure effect on magnetic susceptibility of perovskite manganite La0.66Ba0.34MnO3}, journal = {Journal of Magnetism and Magnetic Materials}, year = {2002}, volume = {241}, number = {1}, pages = {69-72}, doi = {http://dx.doi.org/10.1016/S0304-8853(01)00943-X} }
Beznosov A., Fertman E., Pal-Val P., Desnenko V., Krasovitskij V., Rinkevich A., Nosov A., Vasil'ev V.	Elastic, magnetic and electric properties of Nd0.6Y0.06Ca0.3MnO3: Ordering and randomization effects [BibTeX]	2002	Izvestiya Akademii Nauk. Ser. Fizicheskaya Vol. 66(6), pp. 761-764	URL
BibTeX: @article{Beznosov2002761, author = {Beznosov, A.B. and Fertman, E.L. and Pal-Val, P.P. and Desnenko, V.A. and Krasovitskij, V.B. and Rinkevich, A.B. and Nosov, A.P. and Vasil'ev, V.G.}, title = {Elastic, magnetic and electric properties of Nd0.6Y0.06Ca0.3MnO3: Ordering and randomization effects}, journal = {Izvestiya Akademii Nauk. Ser. Fizicheskaya}, year = {2002}, volume = {66}, number = {6}, pages = {761-764}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-37549013916&partnerID=40&md5=6d98ee251026422622d6255d72372ebc} }
Beznosov A., Eremenko V., Fertman E., Desnenko V., Khalyavin D.	Magnetic phases in La0.66Ba0.34MnO3: Effects of temperature and elastic strains [Abstract] [BibTeX]	2002	Low Temperature Physics Vol. 28(10), pp. 762-766	DOI
Abstract: The static magnetization MN and dynamic magnetic susceptibility χac of polycrystalline manganite La0.66Ba 0.34MnO3 are investigated in the temperature region 5K<T<350K. Measurements are made on a sample with a demagnetizing factor N=5.4 in static magnetic fields H in the range 0-120 Oe and on a toroidal sample with N=0 in fields with frequencies of 120 and 1000 Hz and amplitudes from 8×10-3 to 4.1 Oe. The effect of a uniaxial pressure P=0.1kbar on the static susceptibility χN=MN/H is investigated in the region 5K<T<270K. It is found that in the magnetically ordered state (below 314 K) χac is independent of the field amplitude in the interval 1.5-4.1 Oe and independent of temperature between 250 and 302 K. At a temperature Tp=250K a second-order phase transition (discontinuity of the derivative ∂χac/∂T) is observed, and at T i=177.5K - a first-order phase transition (discontinuity of χac(T)). The uniaxial pressure leads to an anomalous lowering of the susceptibility in the region 160-250 K with a sharp minimum at 200 K. The temperature and field dependence of the magnetic susceptibility outside the phase transition region are interpreted in terms of ideas about the formation of a helicoidal magnetic structure in the system in low fields at a temperature below 302 K.
BibTeX: @article{Beznosov2002762, author = {Beznosov, A.B. and Eremenko, V.V. and Fertman, E.L. and Desnenko, V.A. and Khalyavin, D.D.}, title = {Magnetic phases in La0.66Ba0.34MnO3: Effects of temperature and elastic strains}, journal = {Low Temperature Physics}, year = {2002}, volume = {28}, number = {10}, pages = {762-766}, doi = {http://dx.doi.org/10.1063/1.1521296} }
Grechnev G., Ahuja R., Johansson B., Eriksson O.	Electronic structure, magnetic, and cohesive properties of LixMn2O4: Theory [Abstract] [BibTeX]	2002	Physical Review B - Condensed Matter and Materials Physics Vol. 65(17), pp. 1744081-1744087	DOI
Abstract: The volume dependent electronic structure of the spinel-type lithium manganese oxides LixMn2O4, x =0,0.5,1, is studied ab initio by employing a full-potential electronic structure method. The electronic structure, total energies, open-circuit voltage, and magnetic moments were obtained for various spin configurations of LixdMn2O4 in the cubic spinel structure and the low-temperature orthorhombic structure. The effect of magnetic ordering on the band structure and structural stability has been investigated and an antiferromagnetic ordering proved to be the ground state of the LixMn2O4 spinels. Our calculations show that the manganese majority t2g d band is filled for all LixMn2O4 compounds studied, and the filling of the minority t2g band is expected in the lithiation process. The lithium intercalation potential, bulk modulus, magnetic moments, and optical properties are calculated within the itinerant band approach and are found to be in good agreement with available experimental data, indicating, that the density-functional theory provides reliable electronic structure of the LixMn2O4 system. The effect of the orthorhombic distortion on electronic structure and magnetism of LiMn2O4 was investigated, and our calculations do not show a substantial charge ordering at the structural transition from the cubic spinel to the orthorhombic structure, as proposed earlier. Instead, the low-temperature orthorhombic structure is found to possess the lowest energy via a Jahn-Teller distortion driven by the d band.
BibTeX: @article{Grechnev20021744081, author = {Grechnev, G.E. and Ahuja, R. and Johansson, B. and Eriksson, O.}, title = {Electronic structure, magnetic, and cohesive properties of LixMn2O4: Theory}, journal = {Physical Review B - Condensed Matter and Materials Physics}, year = {2002}, volume = {65}, number = {17}, pages = {1744081-1744087}, doi = {http://dx.doi.org/10.1103/PhysRevB.65.174408} }
Hugosson H., Grechnev G., Ahuja R., Helmersson U., Sa L., Eriksson O.	Stabilization of potential superhard RuO2 phases: A theoretical study [Abstract] [BibTeX]	2002	Physical Review B - Condensed Matter and Materials Physics Vol. 66(17), pp. 1741111-1741117	DOI
Abstract: First-principles full-potential linear muffin-tin orbital calculations have been used to study RuO2 in the fluorite (CaF2) and rutile structures. An investigation of the effects of metal and nonmetal alloying, oxygen vacancies, and lattice strain on the phase stabilities and electronic structure has been made. From these theoretical results suggestions on how the cubic phase may be stabilized are made. The pressure induced phase transitions between the rutile, CaCl2, Pa3 and fluorite phases and the bulk moduli of several 4d and 5d transition metal dioxides have also been studied.
BibTeX: @article{Hugosson20021741111, author = {Hugosson, H.W. and Grechnev, G.E. and Ahuja, R. and Helmersson, U. and Sa, L. and Eriksson, O.}, title = {Stabilization of potential superhard RuO2 phases: A theoretical study}, journal = {Physical Review B - Condensed Matter and Materials Physics}, year = {2002}, volume = {66}, number = {17}, pages = {1741111-1741117}, doi = {http://dx.doi.org/10.1103/PhysRevB.66.174111} }
Ignatova T., Zvyagina G., Kolobov I., Masalitin E., Fil' V., Paderno Y., Bykov A., Paderno V., Lyashenko V.	MgB2: Synthesis, sound velocity, and dynamics of the vortex phase [Abstract] [BibTeX]	2002	Low Temperature Physics Vol. 28(3), pp. 190-193	DOI
Abstract: The sound velocity is measured in polycrystalline MgB2 synthesized from the constituent elements, and the bulk modulus in compression and the Debye temperature are calculated. The conversion of an elastic wave into electromagnetic radiation is investigated in the mixed state. The dynamic parameters of the vortex lattice are estimated.
BibTeX: @article{Ignatova2002190, author = {Ignatova, T.V. and Zvyagina, G.A. and Kolobov, I.G. and Masalitin, E.A. and Fil', V.D. and Paderno, Yu.V. and Bykov, A.N. and Paderno, V.N. and Lyashenko, V.I.}, title = {MgB2: Synthesis, sound velocity, and dynamics of the vortex phase}, journal = {Low Temperature Physics}, year = {2002}, volume = {28}, number = {3}, pages = {190-193}, doi = {http://dx.doi.org/10.1063/1.1468522} }
Kharchenko N., Desnenko V., Kharchenko Y., Szymczak R., Baran M.	Nonmonotonic temperature dependence of the spontaneous magnetization of the antiferromagnetic crystal LiCoPO4 [Abstract] [BibTeX]	2002	Low Temperature Physics Vol. 28(8-9), pp. 646-652	DOI
Abstract: The temperature dependence of the magnitude of the weak ferromagnetic moment is measured in the many-sublattice antiferromagnetic magnetoelectric crystal LiCoPO4. The dependence is found to be nonmonotonic - as the temperature is decreased below the Néel temperature TN, the ferromagnetic moment initially increases and then decreases markedly. It reaches its highest value, close to 0.12 G, at a temperature of around 10.5 K, which is roughly TN/2. The possible mechanisms for the appearance of weak ferromagnetism in LiCoPO4 and the causes of the nonmonotonic temperature dependence of the spontaneous magnetic moment are discussed. Among the possible mechanisms, there is a preference for one in which the weak ferromagnetism is due to a nonuniform antiferromagnetic structure which is proposed for this crystal.
BibTeX: @article{Kharchenko2002646, author = {Kharchenko, N.F. and Desnenko, V.A. and Kharchenko, Y.N. and Szymczak, R. and Baran, M.}, title = {Nonmonotonic temperature dependence of the spontaneous magnetization of the antiferromagnetic crystal LiCoPO4}, journal = {Low Temperature Physics}, year = {2002}, volume = {28}, number = {8-9}, pages = {646-652}, doi = {http://dx.doi.org/10.1063/1.1511710} }
Panfilov A., Grechnev G., Svechkarev I., Sugawara H., Sato H., Eriksson O.	Effect of pressure on the magnetic susceptibility of CeCo2 [Abstract] [BibTeX]	2002	Physica B: Condensed Matter Vol. 319(1-4), pp. 268-276	DOI
Abstract: The magnetic susceptibility, χ, of CeCo2 compound has been measured under pressure up to 2 kbar at T = 78 and 300 K, and a pronounced pressure effect, d ln χ/dP ≃ - 5 Mbar-1, is revealed. In order to analyze the experimental magnetovolume effect, d ln χ/d ln V, the volume-dependent electronic structure of CeCo2 has been calculated ab initio by employing a relativistic full-potential LMTO method. The calculations have brought out strong hybridization of the itinerant 4f (Ce) and 3d (Co) states, which leads to a filling of the peculiar bonding band. It is demonstrated that the magnetic properties of CeCo2 are consistent with itinerant behavior of the 4f electrons of cerium. The large volume derivative of the effective electron-electron interaction parameter, d ln I/d ln V ≃ - 1.7, implies a predominant role of the short-range correlations, in accordance with the Hubbard model.
BibTeX: @article{Panfilov2002268, author = {Panfilov, A.S. and Grechnev, G.E. and Svechkarev, I.V. and Sugawara, H. and Sato, H. and Eriksson, O.}, title = {Effect of pressure on the magnetic susceptibility of CeCo2}, journal = {Physica B: Condensed Matter}, year = {2002}, volume = {319}, number = {1-4}, pages = {268-276}, doi = {http://dx.doi.org/10.1016/S0921-4526(02)01128-6} }
Panfilov A., Pushkar' Y.	Measurement of the densities of liquids and gases under pressure using magnetic levitation of a standard sample [Abstract] [BibTeX]	2002	Low Temperature Physics Vol. 28(10), pp. 789-793	DOI
Abstract: A simple method is proposed for measuring the pressure dependence of the density of gases and liquids in a wide temperature range. The method is based on the principle of free suspension of a standard paramagnetic sample in a nonuniform magnetic field, when the magnetic force compensates the weight of the sample, taking account of the hydrostatic support of the medium. As an example of the application of the method, the density of helium gas up to pressure ∼2.5kbar at temperatures 20.4 and 77.3 K is determined.
BibTeX: @article{Panfilov2002789, author = {Panfilov, A.S. and Pushkar', Yu.Ya.}, title = {Measurement of the densities of liquids and gases under pressure using magnetic levitation of a standard sample}, journal = {Low Temperature Physics}, year = {2002}, volume = {28}, number = {10}, pages = {789-793}, doi = {http://dx.doi.org/10.1063/1.1521301} }
Seidov Z., Seidov Z., Krug von Nidda H.-A., Hemberger J., Loidl A., Sultanov G., Kerimova E., Panfilov A.	Magnetic susceptibility and ESR study of the covalent-chain antiferromagnets TlFeS2 and TlFeSe2 [Abstract] [BibTeX]	2002	Physical Review B - Condensed Matter and Materials Physics Vol. 65(1), pp. 144331-144337	DOI
Abstract: We report on magnetic susceptibility, magnetization, electric resistivity, and ESR experiments on single crystals of the covalent-chain antiferromagnetic compounds TlFeX2 (X=S, Se). Collinear magnetic order with strongly reduced moments sets in at TN=196 K for TlFeS2 and at TN=290 K for TlFeSe2, respectively. The magnetic moments are oriented perpendicular to the chain direction. The temperature dependence of the electric resistivity reveals semiconducting behavior for both compounds. However, high-temperature susceptibility and ESR measurements strongly suggest a one-dimensional metallic character.
BibTeX: @article{Seidov2002144331, author = {Seidov, Z. and Seidov, Z. and Krug von Nidda, H.-A. and Hemberger, J. and Loidl, A. and Sultanov, G. and Kerimova, E. and Panfilov, A.}, title = {Magnetic susceptibility and ESR study of the covalent-chain antiferromagnets TlFeS2 and TlFeSe2}, journal = {Physical Review B - Condensed Matter and Materials Physics}, year = {2002}, volume = {65}, number = {1}, pages = {144331-144337}, doi = {http://dx.doi.org/10.1103/PhysRevB.65.014433} }
Zvyagin A.A., Zvyagina G.A.	Electron paramagnetic resonance with parallel pumping in quantum spin chains with field-induced spin gap [Abstract] [BibTeX]	2002	Physical Review B - Condensed Matter and Materials Physics Vol. 66(1), pp. 144421-1444212	DOI
Abstract: Recently several compounds were observed to reveal properties of a one-dimensional spin-1/2 antiferromagnetic Heisenberg chain with gapless low-lying spin excitations in an absence of an external magnetic field. However even a very weak external magnetic field yields an onset of a spin gap for those low-lying excitations. Usually this onset of a field-induced spin gap is related to the presence of a staggered Dzyaloshinskii-Moriya interaction, or to the staggered effective g factors of magnetic ions. Experiments on thermodynamic properties cannot distinguish between those two origins for the spin-gap formation. Here we propose the setup for an experiment, in which one can clearly distinguish between the staggered Dzyaloshinskii-Moriya coupling and staggered external magnetic field: an electronic paramagnetic resonance in the parallel pumping geometry. The characteristics of the system under conditions of such an experiment, i.e., the renormalization of the homogeneous and staggered magnetizations, power of the microwave magnetic field, absorbed by the system, are calculated. Several important features of the solution are discussed.
BibTeX: @article{Zvyagin2002144421, author = {Zvyagin, A. A. and Zvyagina, G. A.}, title = {Electron paramagnetic resonance with parallel pumping in quantum spin chains with field-induced spin gap}, journal = {Physical Review B - Condensed Matter and Materials Physics}, year = {2002}, volume = {66}, number = {1}, pages = {144421-1444212}, doi = {http://dx.doi.org/10.1103/PhysRevB.66.014442} }
Beznosov A., Fertman E., Eremenko V., Desnenko V.	Electronic structure and magnetostrictive sensitivity of Fe-B metallic glasses [Abstract] [BibTeX]	2001	Low Temperature Physics Vol. 27(4), pp. 316-319	DOI
Abstract: The effect of mechanical tensile stresses 0≤σ≤62 MPa on the low-field (0≤H≤45 Oe) magnetization curves of the metallic glasses Fe 100-xBx (x=14,16,17,20) is studied at temperatures of 77 and 300 K. The correlation between the electronic structure of the glasses and their magnetostrictive sensitivity κs is revealed: the eutectic metallic glass Fe83B17, which possesses a special electronic structure with a 30% lower conduction (sp) electron density, has a value of κs differing substantially from that of the other metallic glasses studied. Under low stresses (0≤σ≤22 MPa) the eutectic alloy possesses a magnetostrictive sensitivity κ s(σ1) which is higher than that of the rest of the alloys studied, while under high stresses (22 MPa≤σ≤62 MPa) its magnetostrictive sensitivity κs(σ2) is close to zero.
BibTeX: @article{Beznosov2001316, author = {Beznosov, A.B. and Fertman, E.L. and Eremenko, V.V. and Desnenko, V.A.}, title = {Electronic structure and magnetostrictive sensitivity of Fe-B metallic glasses}, journal = {Low Temperature Physics}, year = {2001}, volume = {27}, number = {4}, pages = {316-319}, doi = {http://dx.doi.org/10.1063/1.1365608} }
Desnenko V., Fertman E.	Low temperature magnetic sensor based on the age-hardenable Fe-Cr-Ni alloy [Abstract] [BibTeX]	2001	Sensors and Actuators, A: Physical Vol. 91(1-2), pp. 120-122	DOI
Abstract: Low temperature magnetic sensor based on the age-hardenable austenite Fe-Cr-Ni alloy doped by Ti and Al is offered. The sensor operation temperature corresponding to the alloy Curie temperature may be regulated within about the 40 K temperature range by the alloy heat treatment due to the varying of magnetic atoms ratio in the austenite matrix.
BibTeX: @article{Desnenko2001120, author = {Desnenko, V.A and Fertman, E.L}, title = {Low temperature magnetic sensor based on the age-hardenable Fe-Cr-Ni alloy}, journal = {Sensors and Actuators, A: Physical}, year = {2001}, volume = {91}, number = {1-2}, pages = {120-122}, doi = {http://dx.doi.org/10.1016/S0924-4247(01)00504-0} }
Dolya S., Zaslavskii O.	A general approach to potentials with two known levels [Abstract] [BibTeX]	2001	Journal of Physics A: Mathematical and General Vol. 34(10), pp. 1981-1989	DOI
Abstract: We present the general form of potentials with two given energy levels E1 and E2 and find the corresponding wavefunctions. These entities are expressed in terms of one function ξ(x) and one parameter ΔE = E2 - E1. We show how the quantum numbers of both levels depend on the properties of the function ξ(x). Our approach does not require one to resort to the technique of supersymmetric quantum mechanics but generates the expression for the superpotential automatically.
BibTeX: @article{Dolya20011981, author = {Dolya, S.N. and Zaslavskii, O.B.}, title = {A general approach to potentials with two known levels}, journal = {Journal of Physics A: Mathematical and General}, year = {2001}, volume = {34}, number = {10}, pages = {1981-1989}, doi = {http://dx.doi.org/10.1088/0305-4470/34/10/303} }
Dolya S., Zaslavskii O.	Quasi-exactly solvable quartic Bose Hamiltonians [Abstract] [BibTeX]	2001	Journal of Physics A: Mathematical and General Vol. 34(30), pp. 5955-5968	DOI
Abstract: We consider Hamiltonians, which are even polynomials of the fourth order with respect to Bose operators. We find subspaces, preserved by the action of the Hamiltonian. These subspaces, being finite dimensional, include, nonetheless, states with an infinite number of quasi-particles, corresponding to the original Bose operators. The basis functions look rather simple in the coherent state representation and are expressed in terms of the degenerate hypergeometric function with respect to the complex variable labelling the representation. In some particular degenerate cases they turn (up to the power factor) into trigonometric or hyperbolic functions, Bessel functions or combinations of the exponent and Hermite polynomials. We find explicitly the relationship between coefficients at different powers of Bose operators that ensure quasi-exact solvability of Hamiltonians.
BibTeX: @article{Dolya20015955, author = {Dolya, S.N. and Zaslavskii, O.B.}, title = {Quasi-exactly solvable quartic Bose Hamiltonians}, journal = {Journal of Physics A: Mathematical and General}, year = {2001}, volume = {34}, number = {30}, pages = {5955-5968}, doi = {http://dx.doi.org/10.1088/0305-4470/34/30/307} }
Fil V.	Calculation of the electromagnetic field radiated by an elastic wave in a type-II superconductor [Abstract] [BibTeX]	2001	Low Temperature Physics Vol. 27(12), pp. 993-999	DOI
Abstract: Formulas describing the conversion of an elastic wave into an electromagnetic field at the boundary between a type-II superconductor and the vacuum are obtained which admit passing to both the limiting cases of the normal and Meissner states. A strategy that would permit experimental measurement of the dynamical parameters of the vortex lattice is discussed. It is pointed out that the study of the inertial (Stewart-Tolman) component of the radiated field is a promising area of research.
BibTeX: @article{Fil2001993, author = {Fil, V.D.}, title = {Calculation of the electromagnetic field radiated by an elastic wave in a type-II superconductor}, journal = {Low Temperature Physics}, year = {2001}, volume = {27}, number = {12}, pages = {993-999}, doi = {http://dx.doi.org/10.1063/1.1430841} }
Grechnev G., Panfilov A., Svechekarve I., Kaczowrowski D., Hackemer A., Eriksson O.	Magnetovolume effect in UX3 (X = Si, Ge, and Ga) compounds [Abstract] [BibTeX]	2001	Materials Science Forum Vol. 373-3, pp. 653-656	URL
Abstract: The experimental study of the magnetic susceptibility, χ of the uranium compounds UX3 (X=Si, Ga, Ge) under pressure up to 2 kbar in the temperature range 78-300 K reveals a pronounced pressure effect. The measured volume derivatives dlnχ/dlnV were found to be nearly temperature independent and at T=77.3 K equal to 2.3, 6.8, and 6.9 for USi3, UGa3, and UGe3, respectively. In order to analyze these data, the volume dependent band structures of UX3 have been calculated ab initio in the paramagnetic phase by employing a relativistic full-potential LMTO method. The effect of external magnetic field was included self-consistently by means of the Zeeman operator, as well as including the orbital polarization. The calculations have brought out a predominance of itinerant uranium 5f states at the Fermi energy, as well as competition of the orbital and spin contributions to χ. The calculated field-induced magnetic moments of UX3 and their volume derivatives agree well with the experimental results.
BibTeX: @article{Grechnev2001653, author = {Grechnev, G.E. and Panfilov, A.S. and Svechekarve, I.V. and Kaczowrowski, D. and Hackemer, A. and Eriksson, O.}, title = {Magnetovolume effect in UX3 (X = Si, Ge, and Ga) compounds}, journal = {Materials Science Forum}, year = {2001}, volume = {373-3}, pages = {653-656}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035188574&partnerID=40&md5=ca823d3504e7aee1a601d401018e0537} }
Svechkarev I., Panfilov A., Dolya S., Nakamura H., Shiga M., Schlottmann P.	Magnetovolume effect in YbAgCu4 [Abstract] [BibTeX]	2001	Physical Review B - Condensed Matter and Materials Physics Vol. 64(21), pp. 2144141-2144146	DOI
Abstract: The magnetovolume effect, i.e.; the atomic volume dependence of the magnetic susceptibility, has been investigated for the intermediate valence compound YbAgCu4 in the temperature range of 4.2-300 K. The paramagnetostriction and the pressure dependence of the susceptibility were measured at low and high temperatures, respectively. It is found that the detailed behavior of the susceptibility cannot be explained within the framework of integer valence (Coqblin-Schrieffer model). The Anderson model, which in addition takes into account charge fluctuations, appears to be more appropriate and indicates that the f-level energy rather than its width is sensitive to the atomic volume change in YbAgCu4.
BibTeX: @article{Svechkarev20012144141, author = {Svechkarev, I.V. and Panfilov, A.S. and Dolya, S.N. and Nakamura, H. and Shiga, M. and Schlottmann, P.}, title = {Magnetovolume effect in YbAgCu4}, journal = {Physical Review B - Condensed Matter and Materials Physics}, year = {2001}, volume = {64}, number = {21}, pages = {2144141-2144146}, doi = {http://dx.doi.org/10.1103/PhysRevB.64.214414} }
Zvyagin A., Zvyagina G.	Magnetoelastic effects in low-dimensional magnetic systems [Abstract] [BibTeX]	2001	Low Temperature Physics Vol. 27(4), pp. 300-304	DOI
Abstract: We consider a new realization of magnetoelastic interactions in low-dimensional magnetic systems. We show that low-dimensional spin systems are unstable with respect to the spontaneous appearance of alternating distortions of the positions of the three-dimensional nonmagnetic atoms (ligands) that surround the magnetic ions. Those distortions are supplemented by the spontaneous onset of alternating effective g factors of the magnetic ions in the phase with short-range interactions. We discuss the possibility of observing the effect in a uniform external magnetic field, which in the situation considered produces both magnetization and staggered magnetization of the magnetic subsystem. The connection of the proposed theory with recent experiments on effectively low-dimensional magnetic systems (organic spin chains, heavy-fermion compounds, rare-earth molybdates) is discussed.
BibTeX: @article{Zvyagin2001300, author = {Zvyagin, A.A. and Zvyagina, G.A.}, title = {Magnetoelastic effects in low-dimensional magnetic systems}, journal = {Low Temperature Physics}, year = {2001}, volume = {27}, number = {4}, pages = {300-304}, doi = {http://dx.doi.org/10.1063/1.1365605} }
Bengus V., Beznosov A., Desnenko V., Eremenko V., Fertman E., Tabachnikova E.	Anomalies of mechanical and physical properties of the Fe83B17 eutectic metallic glass and their connection with the peculiarities of nanoclusterous structure [Abstract] [BibTeX]	2000	Materials Science Forum Vol. 343, pp. I/-	URL
Abstract: Singularities (anomalies) of mechanical, magnetic and optical characteristics: minima of the critical shear stress, low temperature thermal expansion, saturation magnetization, initial and maximum magnetic permeabilities, sp-conducting electrons density, g-factor, the stress sensitivity of some magnetic characteristics of the stoichiometric Fe83B17 eutectic metallic glass are established. This eutectic metallic glass possess the least sensitivity of atomic and electronic structures to applied loads and lowering temperature that evidences the most stability of atomic and electronic structure of its nanoclusters. The least density of conduction electrons in this glass is connected with the change of the electron configuration of local 3d-shells of Fe ions, considered as the increasing of their effective occupation. Analysis of anomalies of mechanical characteristics in the framework of the polycluster model of amorphous solids allowed estimating of decreased concentrations of coincident atomic sites at intercluster boundaries of the eutectic metallic glass.
BibTeX: @conference{Bengus2000, author = {Bengus, V. and Beznosov, A. and Desnenko, V. and Eremenko, V. and Fertman, E. and Tabachnikova, E.}, title = {Anomalies of mechanical and physical properties of the Fe83B17 eutectic metallic glass and their connection with the peculiarities of nanoclusterous structure}, journal = {Materials Science Forum}, publisher = {Trans Tech Publ, Uetikon-Zuerich, Switzerland}, year = {2000}, volume = {343}, pages = {I/-}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033718856&partnerID=40&md5=2f13a126ead076c6dd6f931e16444b4e} }
Bezuglyi E., Gaiduk A., Fil V., Zherlitsyn S., Zherlitsyn S., Johnson W., Bruls G., Lüthi B., Wolf B.	Electron renormalization of sound interaction with two-level systems in superconducting metallic glasses [Abstract] [BibTeX]	2000	Physical Review B - Condensed Matter and Materials Physics Vol. 62(10), pp. 6656-6664	DOI
Abstract: The crossing of the temperature dependencies of sound velocity in the normal and the superconducting state of metallic glasses indicates renormalization of the intensity of sound interaction with two-level systems (TLS's) caused by their coupling with electrons. In this paper we examine different theoretical approaches to a quantitative description of the renormalization, using the results of a low-temperature ultrasonic investigation of Zr41.2Ti13.8Cu12.5Ni10Be 22.5 amorphous alloy. It is shown that the adiabatic renormalization of the coherent tunneling amplitude can explain only part of the whole effect observed in the experiment. There exists another mechanism of the renormalization affecting only nearly symmetric TLS's, which may be associated with the effect of electron density fluctuations on the interwell potential.
BibTeX: @article{Bezuglyi20006656, author = {Bezuglyi, E.V. and Gaiduk, A.L. and Fil, V.D. and Zherlitsyn, S. and Zherlitsyn, S. and Johnson, W.L. and Bruls, G. and Lüthi, B. and Wolf, B.}, title = {Electron renormalization of sound interaction with two-level systems in superconducting metallic glasses}, journal = {Physical Review B - Condensed Matter and Materials Physics}, year = {2000}, volume = {62}, number = {10}, pages = {6656-6664}, doi = {http://dx.doi.org/10.1103/PhysRevB.62.6656} }
Dolya S., Zaslavskii O.	The quantum anharmonic oscillator and quasi-exactly solvable Bose systems [Abstract] [BibTeX]	2000	Journal of Physics A: Mathematical and General Vol. 33(41), pp. L369-L374	DOI
Abstract: We extend the notion of quasi-exactly solvable (QES) models from potential ones and differential equations to Bose systems. We obtain conditions under which algebraization of part of the spectrum occurs. In some particular cases simple exact expressions for several energy levels of an anharmonic Bose oscillator are obtained explicitly. The corresponding results do not exploit perturbation theory and include the strong-coupling regime. A generic Hamiltonian under discussion cannot, in contrast to QES potential models, be expressed as a polynomial in generators of sl2 algebra. The suggested approach is extendable to many-particle Bose systems with interaction.
BibTeX: @article{Dolya2000, author = {Dolya, S.N. and Zaslavskii, O.B.}, title = {The quantum anharmonic oscillator and quasi-exactly solvable Bose systems}, journal = {Journal of Physics A: Mathematical and General}, year = {2000}, volume = {33}, number = {41}, pages = {L369-L374}, doi = {http://dx.doi.org/10.1088/0305-4470/33/41/102} }
Zvyagin A., Zvyagina G.	Staggered magnetization and realization of Jahn-Teller-like effects [Abstract] [BibTeX]	2000	Physical Review B - Condensed Matter and Materials Physics Vol. 62(17), pp. 11511-11516	DOI
Abstract: A realization for the cooperative Jahn-Teller-like effect in low-dimensional quantum critical systems is proposed. We show that at low temperatures these systems are unstable with respect to the spontaneous appearance of alternating effective g factors, which also pertain to nonzero alternating distortions of ligands, surrounding magnetic ions. The effect is magnetic field-induced. The proposed effect is discussed in connection with recent experiments on effectively low-dimensional electron systems.
BibTeX: @article{Zvyagin200011511, author = {Zvyagin, A.A. and Zvyagina, G.A.}, title = {Staggered magnetization and realization of Jahn-Teller-like effects}, journal = {Physical Review B - Condensed Matter and Materials Physics}, year = {2000}, volume = {62}, number = {17}, pages = {11511-11516}, doi = {http://dx.doi.org/10.1103/PhysRevB.62.11511} }
Zvyagina G., Zvyagin A.	Direct observation of a manifestation of magnetoelastic coupling in a low-dimensional virtual ferroelastic [Abstract] [BibTeX]	2000	Low Temperature Physics Vol. 26(5), pp. 354-362	DOI
Abstract: The propagation velocities of acoustical vibrations are measured for different directions of propagation and polarizations in layered alkali molybdates at low temperatures. A comparison is made of the experimentally obtained absolute sound velocities in virtual ferroelastics and in systems with the cooperative Jahn-Teller effect. The temperature dependence of the sound velocities are investigated experimentally in these systems. The change in the sound velocities in an external magnetic field gives the first direct proof of the presence of an interaction between the magnetic and elastic subsystems of a virtual ferroelastic. A comparison with the theoretical calculations suggests the presence of a nonlinear coupling of the electronic subsystem with optical phonons.
BibTeX: @article{Zvyagina2000354, author = {Zvyagina, G.A. and Zvyagin, A.A.}, title = {Direct observation of a manifestation of magnetoelastic coupling in a low-dimensional virtual ferroelastic}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {2000}, volume = {26}, number = {5}, pages = {354-362}, doi = {http://dx.doi.org/10.1063/1.593908} }
Beznosov A., Fertman E., Eremenko V., Desnenko V., Bengus V.	Magnetic properties and stress effects in glassy Fe-B alloys: the eutectic region [Abstract] [BibTeX]	1999	Digests of the Intermag Conference, pp. GS-16	URL
Abstract: The amorphous alloys Fe100-xBx are soft magnetic materials with a wide range of applications. In this article, data is presented, showing that the electronic structure is the least stable for the threshold hypoeutectic alloy Fe84B16 and the most stable for the eutectic one. This observation is in agreement with the idea of special, probably, quasicrystal, cluster structure of amorphous alloy Fe83B17.
BibTeX: @conference{Beznosov1999, author = {Beznosov, A.B. and Fertman, E.L. and Eremenko, V.V. and Desnenko, V.A. and Bengus, V.Z.}, title = {Magnetic properties and stress effects in glassy Fe-B alloys: the eutectic region}, journal = {Digests of the Intermag Conference}, publisher = {IEEE, Piscataway, NJ, United States}, year = {1999}, pages = {GS-16}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033299619&partnerID=40&md5=16bb52a0e43b64af7054da32bcad6638} }
Beznosov A., Fertman E., Eremenko V., Desnenko V., Bengus V.	Low-temperature magnetic properties and stress effects in glassy Fe-B alloys: The eutectic region [Abstract] [BibTeX]	1999	Low Temperature Physics Vol. 25(8-9), pp. 641-644	DOI
Abstract: The magnetic properties of glassy Fe100-xBx (x = 14,16,17,20) alloys under a low mechanical stress (up to 68 MPa) at temperatures 10-300 K, in magnetic fields up to 40 Oe, have been studied. Low temperature anomalies of magnetic susceptibility, as well as substantial differences in the effects of stresses on the low field magnetic characteristics of alloys with various boron contents, have been revealed. The eutectic alloy Fe83B17 was found to be the least sensitive to applied stresses, magnetic fields, and temperature changes: it possesses the lowest magnetic induction in the reversibility fields region and the highest local anisotropy fluctuations. The hypoeutectic Fe84B16 alloy is the most sensitive to applied stresses at room temperature, but its sensitivity substantially reduces with increasing load, as well as with decreasing temperature. The results obtained reflect the special character of the alloys electronic structure at the eutectic point.
BibTeX: @article{Beznosov1999641, author = {Beznosov, A.B. and Fertman, E.L. and Eremenko, V.V. and Desnenko, V.A. and Bengus, V.Z.}, title = {Low-temperature magnetic properties and stress effects in glassy Fe-B alloys: The eutectic region}, journal = {Low Temperature Physics}, year = {1999}, volume = {25}, number = {8-9}, pages = {641-644}, doi = {http://dx.doi.org/10.1063/1.593793} }
Bezuglyǐ E., Gaiduk A., Fil V., Johnson W., Bruls G., Lüthi B., Wolf B., Zherlitsyn S.	Sound attenuation in the superconducting amorphous alloy ZrTiCuNiBe [Abstract] [BibTeX]	1999	Low Temperature Physics Vol. 25(12), pp. 999-1002	DOI
Abstract: The superconducting energy gap and the parameter η determining the intensity of electron scattering at two-level systems in amorphous ZrTiCuNiBe are determined from the results of measurements of sound attenuation. The mechanism of adiabatic renormalization of the amplitude of coherent tunneling is used for a quantitative description of the peculiarities of sound absorption in the vicinity of Tc.
BibTeX: @article{Bezuglyǐ1999999, author = {Bezuglyǐ, E.V. and Gaiduk, A.L. and Fil, V.D. and Johnson, W.L. and Bruls, G. and Lüthi, B. and Wolf, B. and Zherlitsyn, S.V.}, title = {Sound attenuation in the superconducting amorphous alloy ZrTiCuNiBe}, journal = {Low Temperature Physics}, year = {1999}, volume = {25}, number = {12}, pages = {999-1002}, doi = {http://dx.doi.org/10.1063/1.593855} }
Grechnev G., Panfilov A., Svechkarev I., Delin A., Johansson B., Wills J., Eriksson O.	Magnetovolume effect in UGa3 [Abstract] [BibTeX]	1999	Journal of Magnetism and Magnetic Materials Vol. 192(1), pp. 137-147	DOI
Abstract: The magnetic susceptibility χ of the itinerant antiferromagnetic compound UGa3 has been studied experimentally under pressure up to 2 kbar in the temperature range 64-300 K. This study reveals a pronounced pressure effect on magnetic properties of UGa3 and the measured pressure derivative of the Néel temperature is found to be dTN/dP=-1.1 K/kbar. In order to analyze the experimental magnetovolume effect, to be specific d ln χ/d ln V, the volume dependent electronic structure of UGa3 has been calculated ab initio in the paramagnetic phase by employing a relativistic full-potential LMTO method. The effect of the external magnetic field was included self-consistently by means of the Zeeman operator, as well as orbital polarization. The calculations have brought out a predominance of itinerant uranium 5f states at the Fermi energy, as well as large and competing orbital and spin contributions to χ. The calculated field-induced magnetic moment of UGa3 and its volume derivative compare favorably with our experimental results.
BibTeX: @article{Grechnev1999137, author = {Grechnev, G.E. and Panfilov, A.S. and Svechkarev, I.V. and Delin, A. and Johansson, B. and Wills, J.M. and Eriksson, O.}, title = {Magnetovolume effect in UGa3}, journal = {Journal of Magnetism and Magnetic Materials}, publisher = {Elsevier}, year = {1999}, volume = {192}, number = {1}, pages = {137-147}, doi = {http://dx.doi.org/10.1016/S0304-8853(98)00372-2} }
Panfilov A.	Effect of pressure on magnetic properties of the compound MnSi [Abstract] [BibTeX]	1999	Low Temperature Physics Vol. 25(6), pp. 432-435	DOI
Abstract: Magnetic susceptibility of the weak itinerant-electron ferromagnet MnSi (TC≃30K) is studied in the paramagnetic state under hydrostatic pressure up to 2 kbar in the temperature interval 78-300 K. An analysis of the experimental data using the Stoner model modified to account for the spin fluctuations leads to the estimate for the volume derivative of effective electron-electron interaction parameter d ln J/d ln V = -1.4±0.1 and of the density of electron states at the Fermi level d ln N(EF)/d ln V=2±0.5. A noticeable volume dependence of J points towards a significant role of electron correlations in the magnetism of this compound.
BibTeX: @article{Panfilov1999432, author = {Panfilov, A.S.}, title = {Effect of pressure on magnetic properties of the compound MnSi}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {1999}, volume = {25}, number = {6}, pages = {432-435}, doi = {http://dx.doi.org/10.1063/1.593762} }
Panfilov A., Svechkarev I., Diko P., Mihalik M., Zentko A.	Effects of alloying and pressure on magnetic properties of itinerant intermetallic compound UFe2 [Abstract] [BibTeX]	1999	Low Temperature Physics Vol. 25(8), pp. 682-689	DOI
Abstract: The ferromagnetic state of the itinerant compound UFe2 correlated with a peak in the density of states at the Fermi level is well known to be strongly suppressed by replacing Fe with other 3d elements. To separate the effect of change in filling of the band from that of its deformation under alloying, the magnetic susceptibility of both quasi-binary alloys U(Fe1-xMex)(2) (Me=Mn, Co) with a varying number of valence electrons and isoelectronic quasi-ternary alloys U(Fe1-xTx)(2), U(Fe0.9-xMn0.1Tx)(2) and U(Fe0.9-xCo0.1Tx)(2) (T=Mn0.5Co0.5) was studied in the temperature range 4.2 K less than or equal to T less than or equal to 300 K. Both effects were found to play important roles in suppression of the ferromagnetic state in UFe2-based alloys. In addition, the magnetic susceptibility of U(Fe1-xMnx)(2) and U(Fe1-xTx)(2) alloys and UCo2 compound have been studied under pressure up to 4 kbar at T=78 and 293 K. The volume dependence of the exchange enhancement in spin paramagnetism of the UFe2 compound and its alloys has been derived from analysis of the pressure effects in the framework of the Stoner model. (C) 1999 American Institute of Physics.
BibTeX: @article{Panfilov1999682, author = {Panfilov, A.S. and Svechkarev, I.V. and Diko, P. and Mihalik, M. and Zentko, A.}, title = {Effects of alloying and pressure on magnetic properties of itinerant intermetallic compound UFe2}, journal = {Low Temperature Physics}, year = {1999}, volume = {25}, number = {8}, pages = {682-689}, doi = {http://dx.doi.org/10.1063/1.593799} }
Pluzhnikov V., Czopnik A., Grechnev G.	The Fermi surface of ErGa3 [Abstract] [BibTeX]	1999	Journal of Physics Condensed Matter Vol. 11(23), pp. 4507-4516	DOI
Abstract: The Fermi surface geometry and cyclotron masses of the antiferromagnet ErGa3 in a magnetic-field-induced paramagnetic phase are determined by using the de Haas-van Alphen effect method. The results are analysed on the basis of ab initio band-structure calculations and compared to corresponding results for the isostructural compounds TmGa3 and LuGa3.
BibTeX: @article{Pluzhnikov19994507, author = {Pluzhnikov, V.B. and Czopnik, A. and Grechnev, G.E.}, title = {The Fermi surface of ErGa3}, journal = {Journal of Physics Condensed Matter}, year = {1999}, volume = {11}, number = {23}, pages = {4507-4516}, doi = {http://dx.doi.org/10.1088/0953-8984/11/23/305} }
Pluzhnikov V., Czopnik A., Eriksson O., Grechnev G., Fomenko Y.	Effect of pressure on the Fermi surface and electronic structure of [formula omitted] [Abstract] [BibTeX]	1999	Low Temperature Physics Vol. 25(8), pp. 670-676	DOI
Abstract: The Fermi surface and cyclotron masses of the [formula omitted] compound are studied by means of the de Haas–van Alphen technique under pressure. Concurrently, the electronic structure is calculated ab initio for the ferromagnetic phase of [formula omitted] The experimental data have been analyzed on the basis of the calculated volume-dependent band structure and compared with available results for isostructural [formula omitted] and [formula omitted] compounds.
BibTeX: @article{Pluzhnikov1999670, author = {Pluzhnikov, V.B. and Czopnik, A. and Eriksson, O. and Grechnev, G.E. and Fomenko, Y.V.}, title = {Effect of pressure on the Fermi surface and electronic structure of [formula omitted]}, journal = {Low Temperature Physics}, year = {1999}, volume = {25}, number = {8}, pages = {670-676}, doi = {http://dx.doi.org/10.1063/1.593797} }
Pluzhnikov V.B., Czopnik A., Grechnev G.E., Savchenko N.V., Suski W.	Band structure and fermi surface of TmGa3 [Abstract] [BibTeX]	1999	Physical Review B - Condensed Matter and Materials Physics Vol. 59(12), pp. 7893-7900	DOI
Abstract: In the present work the Fermi surface geometry and cyclotron masses of a (Formula presented) antiferromagnet in a field-induced paramagnetic phase are determined by using the de Haas–van Alphen–effect method. The results are analyzed on the basis of ab initio band structure calculations for (Formula presented) and (Formula presented)
BibTeX: @article{Pluzhnikov19997893, author = {Pluzhnikov, V. B. and Czopnik, A. and Grechnev, G. E. and Savchenko, N. V. and Suski, W.}, title = {Band structure and fermi surface of TmGa3}, journal = {Physical Review B - Condensed Matter and Materials Physics}, year = {1999}, volume = {59}, number = {12}, pages = {7893-7900}, doi = {http://dx.doi.org/10.1103/PhysRevB.59.7893} }
Svechkarev I., Panfilov A., Dolja S., Nakamura H., Shiga M.	The effect of pressure on the magnetic susceptibility of RInCu4 (R = Gd, Er and Yb) [Abstract] [BibTeX]	1999	Journal of Physics Condensed Matter Vol. 11(22), pp. 4381-4390	DOI
Abstract: The magnetic susceptibility of the intermetallic compounds RInCu4 (R = Gd, Er and Yb) was measured under helium gas pressure up to 2 kbar at the fixed temperatures 78, 150 and 300 K. For YbInCu4, which exhibits a first-order valence phase transition at TV ≃ 40 K, the Grüneisen parameter for the Kondo energy, ΩK ≡ -d ln TK/d ln V = -32, is large and typical for Ce-based heavy-fermion systems in magnitude but opposite in sign. The effect of atomic disorder is discussed on the basis of the data for a chemically disordered sample; the pressure effect at T = 78 K is strongly enhanced due to the spatial dispersion of pressure-sensitive TV, and hence dTV/dP = -2.0 K kbar-1 is obtained by assuming a Gaussian distribution of TV. On the basis of an extrapolation of the experimental pressure dependence, a (P, T) phase diagram is proposed for YbInCu4. Reference compounds with stable f moments, GdInCu4 and ErInCu4, show negligible pressure dependences of the susceptibility.
BibTeX: @article{Svechkarev19994381, author = {Svechkarev, I.V. and Panfilov, A.S. and Dolja, S.N. and Nakamura, H. and Shiga, M.}, title = {The effect of pressure on the magnetic susceptibility of RInCu4 (R = Gd, Er and Yb)}, journal = {Journal of Physics Condensed Matter}, year = {1999}, volume = {11}, number = {22}, pages = {4381-4390}, doi = {http://dx.doi.org/10.1088/0953-8984/11/22/309} }
Svechkarev I., Dolya S.	The role of chemical disorder in the magnetism of YbInCu4 compound [Abstract] [BibTeX]	1999	Low Temperature Physics Vol. 25(11), pp. 889-894	DOI
Abstract: It is found that chemical disorder in the YbInCu4 compound (especially in the Yb sublattice) considerably affects its magnetic properties due to spatial nonuniformity of the temperature Tv of the first-order valence phase transition. The evolution of the magnetic susceptibility during disordering of the stoichiometric compound YbInCu4 is described by the model expression taking into account the Tv dispersion upon the application of pressure and variation of composition of YbIn1- xAgxCu4 solid mixtures. The behavior of the main parameters of the system masked by blurring of the magnetic susceptibility singularity for a disordered sample during phase transition. Among other things, the value of the derivative dTv/dx=203 K is determined. The reason behind an abrupt change in the concentration dependence of dispersion and the paramagnetic Curie temperature is calculated at xc≃0.25.
BibTeX: @article{Svechkarev1999889, author = {Svechkarev, I.V. and Dolya, S.N.}, title = {The role of chemical disorder in the magnetism of YbInCu4 compound}, journal = {Low Temperature Physics}, year = {1999}, volume = {25}, number = {11}, pages = {889-894}, doi = {http://dx.doi.org/10.1063/1.593834} }
Svechkarev I., Panfilov A., Dolja S., Nakamura H., Shiga M.	Effect of pressure on magnetic susceptibility in YbInCu4 compound [Abstract] [BibTeX]	1999	Journal of Magnetism and Magnetic Materials Vol. 196, pp. 893-894	DOI
Abstract: Magnetic susceptibility of the YbInCu4 compound, which exhibits the first-order valence phase transition at T≈40 K, was measured under helium gas pressure up to 2 kbar at fixed temperatures 78, 150 and 300 K. It follows from the data obtained that Gruneisen parameter for the characteristic Kondo temperature GK = -d ln TK/d ln V = -32 is typical for the Ce heavy-fermion systems but opposite in sign. Some peculiarities of the (P, T)-phase diagram for YbInCu4 at high pressure are predicted.
BibTeX: @article{Svechkarev1999893, author = {Svechkarev, I.V. and Panfilov, A.S. and Dolja, S.N. and Nakamura, H. and Shiga, M.}, title = {Effect of pressure on magnetic susceptibility in YbInCu4 compound}, journal = {Journal of Magnetism and Magnetic Materials}, publisher = {Elsevier Science Publishers B.V., Amsterdam}, year = {1999}, volume = {196}, pages = {893-894}, doi = {http://dx.doi.org/10.1016/S0304-8853(98)00979-2} }
Belevtsev B., Dalakova N., Panfilov A.	Non-linear effects in hopping conduction of single-crystal La2CuO4+δ [Abstract] [BibTeX]	1998	Low Temperature Physics Vol. 24(11), pp. 815-822	DOI
Abstract: The unusual non-linear effects in hopping conduction of single-crystal La2CuO4+δ with excess oxygen has been observed. The resistance is measured as a function of the applied voltage U (voltage controlled regime) in the temperature range 5 K≤T≤300 K and voltage range 10-3 - 25 V. At relatively high voltage (approximately at U>0.1 V) the conduction of sample investigated corresponds well to variable-range hopping (VRH). That is, in the range 0.1 V < U ≤ 1 V the conductivity does not depend on U (Ohmic behavior) and the temperature dependence of resistance R(T) follows closely Mott's law of VRH [R∝exp(T0/T)1/4]. In the range of highest applied voltage the conduction has been non-Ohmic: the resistance decreases with increasing U. This non-linear effect is quite expected in the frame of VRH mechanism, since the applied electric field increases the hopping probability. A completely different and unusual conduction behavior is found, however, in the low voltage range (approximately below 0.1 V), where the influence of electric field and (or) electron heating effect on VRH ought to be neglected. Here we have observed strong increase in resistance at increasing U at T ≤20 K, whereas at T>20 K the resistance decreases with increasing U. The magnetoresistance of the sample below 20 K has been positive at low voltage and negative at high voltage. The observed unusual non-Ohmic behavior at low voltage range is attributable to inhomogeneity of the sample, namely, to the enrichment of sample surface with oxygen during the course of the heat treatment of the sample in helium and air atmosphere before measurements. At low enough temperature (below ≈20 K) the surface layer with increased oxygen concentration is presumed to consist of disconnected superconducting regions in a poorly conducting (dielectric) matrix. This allows us to explain the observed unusual non-linear effects in the conduction of sample studied. The results obtained demonstrate that in some cases the measured transport properties of cuprate oxides cannot be attributed to the intrinsic bulk properties.
BibTeX: @article{Belevtsev1998815, author = {Belevtsev, B.I. and Dalakova, N.V. and Panfilov, A.S.}, title = {Non-linear effects in hopping conduction of single-crystal La2CuO4+δ}, journal = {Low Temperature Physics}, year = {1998}, volume = {24}, number = {11}, pages = {815-822}, doi = {http://dx.doi.org/10.1063/1.593683} }
Bezuglyi E., Burma N., Gaiduk A., Kolobov I., Fil V., Khotkevich V., Van Kempen H.	Electron sound in aluminum. Electron-electron scattering [Abstract] [BibTeX]	1998	Low Temperature Physics Vol. 24(3), pp. 169-181	DOI
Abstract: The relaxation parameters of charge carriers in aluminum are measured by investigating the attenuation of electron sound and acoustic wave transfer under Doppler-shifted cyclotron resonance. It is shown that the electron-electron relaxation rate at spherical parts of the hole sheet of the Fermi surface is close to the results of the theory (A. Jaquier et al., Phys. Rev. B52, 13005 (1995)) that takes into account the electron-electron interaction with the exchange of virtual phonons. At the same time, the experimental anisotropy of the electron-electron scattering is considerably smaller than the calculated value. A noticeable anisotropy of the electron-impurity collisions frequency in aluminum is discovered.
BibTeX: @article{Bezuglyi1998169, author = {Bezuglyi, E.V. and Burma, N.G. and Gaiduk, A.L. and Kolobov, I.G. and Fil, V.D. and Khotkevich, V.V. and Van Kempen, H.}, title = {Electron sound in aluminum. Electron-electron scattering}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {1998}, volume = {24}, number = {3}, pages = {169-181}, doi = {http://dx.doi.org/10.1063/1.593567} }
Svechkarev I.V., Panfilov A.S., Dolja S.N., Nakamura H., Shiga M.	Pressure Effect on the Magnetic Susceptibility of the YbInCu4 and GdInCu4 Compounds [Abstract] [BibTeX]	1998	Itinerant Electron Magnetism: Fluctuation Effects (Chapter in Book), pp. 309-321	DOI
Abstract: Pressure effect on the magnetic susceptibility of YbInCu4 and GdInCu4 compounds has been studied at fixed temperatures of 78, 150 and 300 K under helium gas pressure up to 2 kbar. The data for the YbInCu4 compound at T ≥ 100 K are well described in terms of the characteristic Kondo temperature change dTk/dlnV= --- 640 K, which is typical for other Kondo systems and far exceeds the corresponding derivative values for usual mechanisms of the indirect f --- f interaction. Moreover, the last contribution reveals a negligible pressure dependence for the reference GdInCu4 compound. For the YbInCu4 compound at T = 78 K, the pressure effect is significantly enhanced and is explained, in line with the temperature dependence of the susceptibility itself near the transition temperature Tv, in terms of spatial dispersion of its pressure dependence due to some atomic disorder.
BibTeX: @article{svechkarev1998, author = {Svechkarev, I. V. and Panfilov, A. S. and Dolja, S. N. and Nakamura, H. and Shiga, M.}, title = {Pressure Effect on the Magnetic Susceptibility of the YbInCu4 and GdInCu4 Compounds}, journal = {Itinerant Electron Magnetism: Fluctuation Effects (Chapter in Book)}, publisher = {Springer Netherlands}, year = {1998}, pages = {309-321}, doi = {http://dx.doi.org/10.1007/978-94-011-5080-4_18} }
Grechnev G.E., Panfilov A.S., Svechkarev I.V., Delin A., Eriksson O., Johansson B., Wills J.M.	Atomic volume effect on electronic structure and magnetic properties of UGa₃ compound [Abstract] [BibTeX]	1998	Itinerant Electron Magnetism: Fluctuation Effects (Chapter in Book), pp. 323-335	DOI
Abstract: The magnetic susceptibility x of the itinerant antiferromagnetic compound UGa3 has been studied experimentally under pressure up to 2 kbar in the temperature range 64--300 K. This study reveals a pronounced pressure effect on magnetic properties of UGa3 and the measured pressure derivative of the Néel temperature is found to be dTN/dP=-1.1 K/kbar. In order to analyze the experimental magnetovolume effect, to be specific dln x/dln V, the volume dependent electronic structure of UGa3 has been calculated ab initio in the paramagnetic phase by employing a relativistic full-potential LMTO method. The effect of the external magnetic field was included self-consistently by means of the Zeeman operator, as well as orbital polarization. The calculations have brought out a predominance of itinerant uranium 5f states at the Fermi energy, as well as large and competing orbital and spin contributions to x. The calculated field-induced magnetic moment of UGa3 and its volume derivative compare favorably with our experimental results.
BibTeX: @article{grechnev1998, author = {Grechnev, G. E. and Panfilov, A. S. and Svechkarev, I. V. and Delin, A. and Eriksson, O. and Johansson, B. and Wills, J. M.}, title = {Atomic volume effect on electronic structure and magnetic properties of UGa₃ compound}, journal = {Itinerant Electron Magnetism: Fluctuation Effects (Chapter in Book)}, publisher = {Springer Netherlands}, year = {1998}, pages = {323-335}, doi = {http://dx.doi.org/10.1007/978-94-011-5080-4_19} }
Belevtsev B., Dalakova N., Panfilov A.	Superconductivity effects in hopping conductivity of single-crystal La2CuO4 with excess oxygen [Abstract] [BibTeX]	1997	Physica C: Superconductivity and its Applications Vol. 282-287(PART 3), pp. 1223-1224	DOI
Abstract: The transition from variable-range hopping conductivity to simple activated one (the Arrhenius law) is observed in single-crystal La2CuO4+δ) as the temperature is decreased below T ≃ 20 K. It is shown that this effect can be assigned to the presence of superconducting inclusions (of Tc = 15-20 K) in insulating sample. The existence of such inclusions may be related to the well-known phase separation for La2CuO4+δ.
BibTeX: @article{Belevtsev19971223, author = {Belevtsev, B.I. and Dalakova, N.V. and Panfilov, A.S.}, title = {Superconductivity effects in hopping conductivity of single-crystal La2CuO4 with excess oxygen}, journal = {Physica C: Superconductivity and its Applications}, year = {1997}, volume = {282-287}, number = {PART 3}, pages = {1223-1224}, doi = {http://dx.doi.org/10.1016/S0921-4534(97)00798-3} }
Belevtsev B., Dalakova N., Panfilov A.	Superconductivity effects in hopping conductivity of La2CuO4 single crystal with excess oxygen [Abstract] [BibTeX]	1997	Low Temperature Physics Vol. 23(4), pp. 274-280	DOI
Abstract: The hopping conductivity of La2CuO4+δ single crystal with excess oxygen has been studied. It is found that the transition from variable-range hopping (with the temperature dependence of resistance R ∝ exp(T0/T)1/4) to simple activation conductivity (R ∝ exp(Δ/kT)) occurs at a temperature lower than 20 K. This transition is accompanied with significant changes in the behavior of magnetoresistance and current-voltage characteristics. It is shown that such a behavior of hopping conductivity below 20 K is due to the presence of superconducting inclusions in insulating sample due to phase separation of La2CuO4+δ. The observed peculiarities in the conducting properties are in good agreement with the known effects of competition between electron localization and superconductivity in homogeneous systems.
BibTeX: @article{Belevtsev1997274, author = {Belevtsev, B.I. and Dalakova, N.V. and Panfilov, A.C.}, title = {Superconductivity effects in hopping conductivity of La2CuO4 single crystal with excess oxygen}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {1997}, volume = {23}, number = {4}, pages = {274-280}, doi = {http://dx.doi.org/10.1063/1.593396} }
Buschow K., Grechnev G., Hjelm A., Kasamatsu Y., Panfilov A., Svechkarev I.	Magnetic properties of GdM compounds: Role of d-electrons [Abstract] [BibTeX]	1997	Physica B: Condensed Matter Vol. 237-238, pp. 570-571	DOI
Abstract: Magnetic susceptibility of ferromagnetic GdM alloys (M = Mg, Zn, Cd, and Cu1-xGax) has been investigated under pressure for temperatures above TC. The evaluated pressure derivatives of the paramagnetic Curie temperature appeared to be remarkably different for isovalent GdM compounds. Analysis of the experimental data and results of ab initio electronic-structure calculations for GdMg and GdZn have revealed the essential role of 5d electrons as the mediators of exchange coupling in ferromagnetic GdM compounds. The pressure derivatives of Tc were calculated by employing a spin fluctuation theory. As a result, a good agreement is found with the experimental data.
BibTeX: @article{Buschow1997570, author = {Buschow, K.H.J. and Grechnev, G.E. and Hjelm, A. and Kasamatsu, Y. and Panfilov, A.S. and Svechkarev, I.V.}, title = {Magnetic properties of GdM compounds: Role of d-electrons}, journal = {Physica B: Condensed Matter}, year = {1997}, volume = {237-238}, pages = {570-571}, doi = {http://dx.doi.org/10.1016/S0921-4526(97)00257-3} }
Gaiduk A., Bezuglyi E., Fil V., Johnson W.	Low-temperature acoustic characteristics of the amorphous alloy Zr41.2Ti13.8Cu12.5Ni10Be 22.5 [Abstract] [BibTeX]	1997	Low Temperature Physics Vol. 23(10), pp. 857-860	DOI
Abstract: The temperature dependences of the sound velocity υ and attenuation a of high-frequency (50-160 MHz) sound in the bulk amorphous alloy Zr41.2Ti13.8Cu12.5Ni10Be 22.5 are studied at helium temperatures in the normal and superconducting states. The alloy is characterized by a relatively small constant C determining the intensity of interaction between an elastic wave and two-level systems. The density of states of the latter systems is estimated. The peculiarities in the variation of υ during the superconducting transition point to the possibility of a gapless superconductivity in a narrow temperature interval near Tc.
BibTeX: @article{Gaiduk1997857, author = {Gaiduk, A.L. and Bezuglyi, E.V. and Fil, V.D. and Johnson, W.L.}, title = {Low-temperature acoustic characteristics of the amorphous alloy Zr41.2Ti13.8Cu12.5Ni10Be 22.5}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {1997}, volume = {23}, number = {10}, pages = {857-860}, doi = {http://dx.doi.org/10.1063/1.593459} }
Grechnev G., Ushakova N., Kervalishvili P., Kvachantiradze G., Kharebov K.	Electron structure of diborides of 3d metals [Abstract] [BibTeX]	1997	Low Temperature Physics Vol. 23(3), pp. 217-219	DOI
Abstract: The electron energy spectra of diborides of 3d-metals ScB2, TiB2, VB2, CrB2, and MnB2 are calculated ab initio. Thermodynamic properties and stability of these compounds are investigated at low temperatures. An analysis of the low-temperature heat capacity and magnetic properties of diborides has made it possible to establish a number of parameters of many-particle interactions.
BibTeX: @article{Grechnev1997217, author = {Grechnev, G.E. and Ushakova, N.V. and Kervalishvili, P.D. and Kvachantiradze, G.G. and Kharebov, K.S.}, title = {Electron structure of diborides of 3d metals}, journal = {Low Temperature Physics}, publisher = {American Institute of Physics Inc.}, year = {1997}, volume = {23}, number = {3}, pages = {217-219}, doi = {http://dx.doi.org/10.1063/1.593361} }
Grechnev G., Desnenko V., Panfilov A., Svechkarev I., Brommer P., Franse J., Kayzel F.	Pressure effect on electronic structure and magnetic properties of RNi5 [Abstract] [BibTeX]	1997	Physica B: Condensed Matter Vol. 237-238, pp. 532-533	DOI
Abstract: Magnetic susceptibility of RNi5 single crystals (R=Gd, Tb, Dy) was studied under uniform and uniaxial pressures at temperatures above TC. The uniform pressure derivatives of the paramagnetic Curie temperature Θ and the crystalline electric field parameter B0 2 appear to be small. On the other hand, Θ and B0 2 parameters display a large sensitivity to the uniaxial pressure due to related changes of c/a ratio. Ab initio electronic structure calculation was performed for GdNi5 to evaluate the volume derivative of TC.
BibTeX: @article{Grechnev1997532, author = {Grechnev, G.E. and Desnenko, V.A. and Panfilov, A.S. and Svechkarev, I.V. and Brommer, P.E. and Franse, J.J.M. and Kayzel, F.E.}, title = {Pressure effect on electronic structure and magnetic properties of RNi5}, journal = {Physica B: Condensed Matter}, year = {1997}, volume = {237-238}, pages = {532-533}, doi = {http://dx.doi.org/10.1016/S0921-4526(97)00219-6} }
Grechnev G., Panfilov A., Svechkarev I., Czopnik A., Suski W., Hackemer A.	The effect of pressure on the magnetic susceptibility of CeIn3-xSnx alloys [Abstract] [BibTeX]	1997	Journal of Physics Condensed Matter Vol. 9(32), pp. 6921-6930	DOI
Abstract: A transition from the Kondo state to an intermediate-valence state takes place in the quasibinary alloys CeIn3-xSnx with cubic AuCu3-type structure. The effect of pressure P up to 2 kbar on the magnetic susceptibility χ of this system was measured at 78, 150, and 295 K. The value of d In χ/dP obtained is well above those observed for similar RE compounds with stable valences. This derivative tends to decrease with temperature, and to increase (but not monotonically) with the tin content x. The experimental data on d In χ/dp (x,T) were analysed in terms of the changes in the spin-fluctuation temperature Tsf.
BibTeX: @article{Grechnev19976921, author = {Grechnev, G.E. and Panfilov, A.S. and Svechkarev, I.V. and Czopnik, A. and Suski, W. and Hackemer, A.}, title = {The effect of pressure on the magnetic susceptibility of CeIn3-xSnx alloys}, journal = {Journal of Physics Condensed Matter}, year = {1997}, volume = {9}, number = {32}, pages = {6921-6930}, doi = {http://dx.doi.org/10.1088/0953-8984/9/32/014} }
Leszczynski M., Pluzhnikov V., Czopnik A., Bak-Misiuk J., Slupinski T.	Thermal expansion of GaAs:Te and AlGaAs:Te at low temperatures [Abstract] [BibTeX]	1997	Journal of Applied Physics Vol. 82(9), pp. 4678-4680	DOI
Abstract: We studied the influence of free electrons on the lattice parameters, thermal expansion, and negative thermal expansion of GaAs:Te and AlGaAs:Te. The samples were examined at temperatures in the range of 10-295 K. Dylatometry and high-resolution x-ray diffraction were used as experimental techniques. Additionally, for the doped layer of Al0.32Ga0.68As, the free-electron concentration was changed in situ by illumination and emptying the metastable DX centers. These results were compared with those for GaAs bulk crystals examined using dylatometry. It was confirmed that n-type doping increases thermal expansion at temperatures higher than about 120 K. At lower temperatures, a phenomenon of the negative thermal expansion becomes much more pronounced for the doped GaAs sample.
BibTeX: @article{Leszczynski19974678, author = {Leszczynski, M. and Pluzhnikov, V.B. and Czopnik, A. and Bak-Misiuk, J. and Slupinski, T.}, title = {Thermal expansion of GaAs:Te and AlGaAs:Te at low temperatures}, journal = {Journal of Applied Physics}, publisher = {American Institute of Physics Inc.}, year = {1997}, volume = {82}, number = {9}, pages = {4678-4680}, doi = {http://dx.doi.org/10.1063/1.366207} }
Buschow K.H.J., Grechnev G.E., Hjelm A., Kasamatsu Y., Panfilov A.S., Svechkarev I.V.	Exchange coupling in GdM compounds [Abstract] [BibTeX]	1997	Acta Physica Polonica A Vol. 92(2), pp. 267-270	DOI
Abstract: The magnetic susceptibility of ferromagnetic GdM alloys (M=Cu1-xGax, Mg, Zn) has been investigated under helium gas pressure for temperatures above T-C. The evaluated pressure derivatives of the paramagnetic Curie temperature, d ln Theta/dP, appeared to be remarkably different for isovalent GdMg and GdZn compounds (-11.2 and -0.1 Mbar(-1), respectively). An analysis of the obtained d ln Theta/dP values for GdCu1-xGax alloys and results of ab initio electronic structure calculations have revealed the essential role of 5d electrons as the mediators of exchange coupling in ferromagnetic GdM compounds. The pressure derivatives of T-C were calculated by employing the modern mean-field theory, as well as the spin-fluctuation model. As a result, good agreement is found with the experimental values of d ln Theta/dP.
BibTeX: @article{buschow1997, author = {Buschow, K. H. J. and Grechnev, G. E. and Hjelm, A and Kasamatsu, Y and Panfilov, A. S. and Svechkarev, I. V.}, title = {Exchange coupling in GdM compounds}, journal = {Acta Physica Polonica A}, publisher = {POLISH ACAD SCIENCES INST PHYSICS}, year = {1997}, volume = {92}, number = {2}, pages = {267-270}, note = {European Conference on Physics of Magnetism 96, POZNAN, POLAND, JUN 24-28, 1996}, doi = {http://dx.doi.org/10.12693/APhysPolA.92.267} }
Grechnev G.E., Delin A., Eriksson O., Johansson B., Panfilov A.S., Svechkarev I.V., Kaczorowski D.	Pressure effect on magnetic properties of UGa3 [Abstract] [BibTeX]	1997	Acta Physica Polonica A Vol. 92(2), pp. 331-333	DOI
Abstract: The magnetic susceptibility, chi, of the itinerant antiferromagnetic compound UGa3 was studied under pressure up to 2 kbar in the temperature range 64-300 K. The measured pressure derivative of the Neel temperature is found to be dT(N)/dP = -1.1 K/kbar. In order to analyze the experimental magnetovolume effect values, d ln chi/d lnV, the volume dependent electronic structure of UGa3 has been calculated ab initio in a paramagnetic phase by employing a relativistic full-potential linear muffin tin orbital method and including an external magnetic field self-consistently. The calculations revealed a predominance of itinerant uranium f-states at the Fermi energy, as well as a large orbital contribution to chi.
BibTeX: @article{grechnev1997, author = {Grechnev, G. E. and Delin, A and Eriksson, O and Johansson, B and Panfilov, A. S. and Svechkarev, I. V. and Kaczorowski, D}, title = {Pressure effect on magnetic properties of UGa3}, journal = {Acta Physica Polonica A}, publisher = {POLISH ACAD SCIENCES INST PHYSICS}, year = {1997}, volume = {92}, number = {2}, pages = {331-333}, note = {European Conference on Physics of Magnetism 96, POZNAN, POLAND, JUN 24-28, 1996}, doi = {http://dx.doi.org/10.12693/APhysPolA.92.331} }
Buschow K., Grechnev G., Hjelm A., Kasamatsu Y., Panfilov A., Svechkarev I.	Exchange coupling in GdM compounds [Abstract] [BibTeX]	1996	Journal of Alloys and Compounds Vol. 244(1-2), pp. 113-120	DOI
Abstract: The magnetic susceptibility of ferromagnetic GdM alloys (M = Cu1-xGax, Mg, Zn) has been investigated under helium gas pressure for temperatures above TC. The evaluated pressure derivatives of the paramagnetic Curie temperature, d In Θ/dP, appeared to be remarkably different for isovalent GdMg and GdZn compounds (-11.2 Mbar-1 and -0.1 Mbar-1 respectively). Analysis of the obtained d In Θ/dP values for GdCu1-xGax alloys and results of ab initio electronic structure calculations have revealed the essential role of 5d electrons as the mediators of exchange coupling in ferromagnetic GdM compounds. The pressure derivatives of TC were calculated in the frameworks of modern mean-field theories by using volume-dependent band and exchange parameters, and including spin fluctuations effects. As a result, good agreement is found with the experimental values of d In Θ/dP.
BibTeX: @article{Buschow1996113, author = {Buschow, K.H.J. and Grechnev, G.E. and Hjelm, A. and Kasamatsu, Y. and Panfilov, A.S. and Svechkarev, I.V.}, title = {Exchange coupling in GdM compounds}, journal = {Journal of Alloys and Compounds}, year = {1996}, volume = {244}, number = {1-2}, pages = {113-120}, doi = {http://dx.doi.org/10.1016/S0925-8388(96)02431-0} }
Fil V., Gaiduk A., Kolobov I., Ignatovaa T., Fil D., Barilo S., Zhigunov D.	Magnetoelastic effects in Nd2CuO4 single crystals [Abstract] [BibTeX]	1996	Czechoslovak Journal of Physics Vol. 46(SUPPL. 4), pp. 2153-2154	DOI
Abstract: We have measured the anisotropy of the spin reorientation fields in Nd2Cu04 single crystals from the magnetoelastic effects. For T >1.5K our experimental data can be understood it terms of the four-sublattice antiferromagnet nmdel and allow to estimate the relation between the phenomenological constants of the model. For T <1.5K we have found a manifestation of new spin-reorientation field stimulated phase transition. These transitions exist only in narrow range of the angles between the magnetic field and [100] directions and are connected most likely with the Nd spins.
BibTeX: @article{Fil19962153, author = {Fil, V.D. and Gaiduk, A.L. and Kolobov, I.G. and Ignatovaa, T.V. and Fil, D.V. and Barilo, S.N. and Zhigunov, D.I.}, title = {Magnetoelastic effects in Nd2CuO4 single crystals}, journal = {Czechoslovak Journal of Physics}, year = {1996}, volume = {46}, number = {SUPPL. 4}, pages = {2153-2154}, doi = {http://dx.doi.org/10.1007/BF02571068} }
Fil D., Kolobov I., Fil V., Barilo S., Zhigunov D.	Indirect observation of a soundlike collective mode in electronic cuprates [Abstract] [BibTeX]	1996	Czechoslovak Journal of Physics Vol. 46(SUPPL. 4), pp. 2155-2156	DOI
Abstract: We report the results of sound velocity measurements in Nd2CuO4 and Pr2CuO4 single crystals. An unexpected effect is found, which consists in unusual behavior of the velocity of the quasitransverse mode vt at out-of-CuO2 plane direction of the wave vector q. Rotating q from the [100] or [110] to the [001] direction we registered, first, a strong lowering, and, then, a steplike increase of v=. The observed features can be described by a phenomenological model, based on the suggestion about the existence of a sound like collective mode coupled to uzz lattice deformation. All components of the elastic moduli tensor, bulk moduli and Debye temperatures are obtained.
BibTeX: @article{Fil19962155, author = {Fil, D.V. and Kolobov, I.G. and Fil, V.D. and Barilo, S.N. and Zhigunov, D.I.}, title = {Indirect observation of a soundlike collective mode in electronic cuprates}, journal = {Czechoslovak Journal of Physics}, year = {1996}, volume = {46}, number = {SUPPL. 4}, pages = {2155-2156}, doi = {http://dx.doi.org/10.1007/BF02571069} }
Fil V., Bezuglyi E., Burma N., Gaiduk A., Kolobov I., van Kempen H., Deyneka E.	Electron sound in Al [Abstract] [BibTeX]	1996	Czechoslovak Journal of Physics Vol. 46(SUPPL. 5), pp. 2547-2548	DOI
Abstract: Electron sound (ES) represents fast electron mode propagating in metals with the Fermi velocity and possessing linear dispersion law. We have measured the velocity and the amplitude of ES in AI single crystals within a wide range of temperature and magnetic field. It was discovered that in Al the electron-electron scattering yields the main contribution (~T2) in ES attenuation. In contrast to Ga and Mo, ES amplitude in the superconducting state of Al increases sharply just below Tc. The ES in Al represents most likely the sum of two signals of different nature - Fermi-liquid zero sound and ballistic quasiwaves.
BibTeX: @article{Fil19962547, author = {Fil, V.D. and Bezuglyi, E.V. and Burma, N.G. and Gaiduk, A.L. and Kolobov, I.G. and van Kempen, H. and Deyneka, E.Y.}, title = {Electron sound in Al}, journal = {Czechoslovak Journal of Physics}, year = {1996}, volume = {46}, number = {SUPPL. 5}, pages = {2547-2548}, doi = {http://dx.doi.org/10.1007/BF02570260} }
Grechnev G., Panfilov A., Savchenko N., Svechkarev I., Czopnik A., Hackemer A.	Magnetovolume effect in paramagnetic alloys of CeIn3-xSnx [Abstract] [BibTeX]	1996	Journal of Magnetism and Magnetic Materials Vol. 157-158, pp. 677-678	DOI
Abstract: The effect of pressure up to 2 kbar on the magnetic susceptibility of CeIn3-xSnx alloys, exhibiting a transition from Kondo to the intermediate valence state, was studied at 77.5, 150 and 300 K. The obtained magnetovolume effect value, dln χ/dln V, is well above those observed for similar compounds with stable valence. The experimental data have been analyzed assuming a dominant role of changes in the spin fluctuation temperature, TSF, and the band structure under pressure.
BibTeX: @article{Grechnev1996677, author = {Grechnev, G.E. and Panfilov, A.S. and Savchenko, N.V. and Svechkarev, I.V. and Czopnik, A. and Hackemer, A.}, title = {Magnetovolume effect in paramagnetic alloys of CeIn3-xSnx}, journal = {Journal of Magnetism and Magnetic Materials}, year = {1996}, volume = {157-158}, pages = {677-678}, doi = {http://dx.doi.org/10.1016/0304-8853(95)00990-6} }
Grechnev G., Panfilov A., Svechkarev I., Kaczorowski D., Troć R., Czopnik A.	Effect of pressure on magnetic properties of U(Ga1-xSnx) 3 alloys [Abstract] [BibTeX]	1996	Journal of Magnetism and Magnetic Materials Vol. 157-158, pp. 702-703	DOI
Abstract: Magnetic susceptibilities, χ, of U(Ga1 - xSnx)3 alloys (with x = 0 and 0.45) were studied under pressures up to 2 kbar in the temperature range 64-300 K. For UGa3 the pressure dependence of the Néel temperature was found to be dTN/dP = -1.1 ± 0.2 K/kbar. The obtained magnetovolume effect values, dln χ/dln V, and the results of detailed theoretical calculations of the electronic structure of UGa3 for different lattice parameters have been used to evaluate the volume dependence of the effective electron-electron interaction parameter.
BibTeX: @article{Grechnev1996702, author = {Grechnev, G.E. and Panfilov, A.S. and Svechkarev, I.V. and Kaczorowski, D. and Troć, R. and Czopnik, A.}, title = {Effect of pressure on magnetic properties of U(Ga1-xSnx) 3 alloys}, journal = {Journal of Magnetism and Magnetic Materials}, year = {1996}, volume = {157-158}, pages = {702-703}, doi = {http://dx.doi.org/10.1016/0304-8853(96)00013-3} }
Grechnev G., Panfilov A., Svechkarev I.	Pressure effect on the itinerant magnetism of MnSi and FeSi [Abstract] [BibTeX]	1996	Journal of Magnetism and Magnetic Materials Vol. 157-158, pp. 711-712	DOI
Abstract: The pressure effect on the magnetic susceptibility of MnSi and FeSi is studied in the temperature range 78-300 K. The obtained values of the magnetovolume effect in the paramagnetic phase of the monosilicides, and the results of detailed LMTO calculations of density of states at the Fermi level as a function of the lattice constant and temperature, were used to evaluate the volume derivatives of the electron-electron interaction parameter in MnSi and the energy gap in FeSi. The role of spin fluctuations in the magnetovolume effect is discussed.
BibTeX: @article{Grechnev1996711, author = {Grechnev, G.E. and Panfilov, A.S. and Svechkarev, I.V.}, title = {Pressure effect on the itinerant magnetism of MnSi and FeSi}, journal = {Journal of Magnetism and Magnetic Materials}, year = {1996}, volume = {157-158}, pages = {711-712}, doi = {http://dx.doi.org/10.1016/0304-8853(95)00983-3} }
Guretskii S., Ges A., Luginets A., Milovanov A., FiL' V., Zherlitsyn S.	Low-temperature magnetic properties of terbium orthoferrite single crystals [Abstract] [BibTeX]	1996	Crystal Research and Technology Vol. 31(7), pp. 897-902	DOI
Abstract: Spontaneous and by an external magnetic field induced magnetic phase transitions in TbFeO3 have been experimentally studied. Precision investigations of velocities of transmission and attenuation of sound wave were made, the processes of formation and rearrangement of magnetic structure examined and its change under the influence of external magnetic field explored. This has been made possible by the development of methods of controlled growth of rare-earth orthoferrites resulting in the formation of high-quality single crystals of required size with reproducible physical properties. The measurements were taken in the temperature range from 0.45 to 8.0 K. From the threshold field values a Ha - T phase diagram for TbFeO3 has been plotted.
BibTeX: @article{Guretskii1996897, author = {Guretskii, S.A. and Ges, A.P. and Luginets, A.M. and Milovanov, A.S. and FiL', V.D. and Zherlitsyn, S.V.}, title = {Low-temperature magnetic properties of terbium orthoferrite single crystals}, journal = {Crystal Research and Technology}, publisher = {Wiley-VCH Verlag}, year = {1996}, volume = {31}, number = {7}, pages = {897-902}, doi = {http://dx.doi.org/10.1002/crat.2170310716} }
Brommer P., Grechnev G., Franse J., Panfilov A., Pushkar Y.Y., Svechkarev I.	The pressure effect on the enhanced itinerant paramagnetism of Ni3Al and TiCo compounds [Abstract] [BibTeX]	1995	Journal of Physics: Condensed Matter Vol. 7(16), pp. 3173-3180	DOI
Abstract: The pressure effect on the magnetic susceptibility of Ni3Al and TiCo compounds is studied in the temperature range 20-293 K. The obtained magnetovolume effect values dln chi /dlnV and results of detailed theoretical calculations of density of states at the Fermi level as a function of the lattice constant were used to evaluate volume derivatives of the electron-electron interaction parameter J: dlnJ/dlnV=-0.9+or-0.15 (Ni3Al) and -0.95+or-0.15 (TiCo). These results are compared with theoretical estimates of dlnJ/dlnV from ab initio LMTO band structure calculations.
BibTeX: @article{Brommer19953173, author = {Brommer, P.E. and Grechnev, G.E. and Franse, J.J.M. and Panfilov, A.S. and Yu Ya Pushkar and Svechkarev, I.V.}, title = {The pressure effect on the enhanced itinerant paramagnetism of Ni3Al and TiCo compounds}, journal = {Journal of Physics: Condensed Matter}, year = {1995}, volume = {7}, number = {16}, pages = {3173-3180}, doi = {http://dx.doi.org/10.1088/0953-8984/7/16/011} }
Grechnev G., Panfilov A., Svechkarev I., Buschow K., Czopnik A.	Conduction-electron-mediated exchange coupling in heavy rare earth metal compounds RM and RM3 [Abstract] [BibTeX]	1995	Journal of Alloys and Compounds Vol. 226(1-2), pp. 107-112	DOI
Abstract: The effect of pressure on the magnetic susceptibility of rare earth compounds GdM (MCu, Ag, Mg) and RIn3 (RGd, Tb, Dy) has been investigated. The experimental data and results of ab initio calculations of the volume derivatives of the band structure and the exchange parameters for the corresponding series of compounds have been used to analayze the nature of the f-f interactions.
BibTeX: @article{Grechnev1995107, author = {Grechnev, G.E. and Panfilov, A.S. and Svechkarev, I.V. and Buschow, K.H.J. and Czopnik, A.}, title = {Conduction-electron-mediated exchange coupling in heavy rare earth metal compounds RM and RM3}, journal = {Journal of Alloys and Compounds}, year = {1995}, volume = {226}, number = {1-2}, pages = {107-112}, doi = {http://dx.doi.org/10.1016/0925-8388(95)01595-7} }
Panfilov A., Svechkarev I., Troć R., Tran V.	Effect of pressure on magnetic susceptibility of UCu5-xAux alloys [Abstract] [BibTeX]	1995	Journal of Alloys and Compounds Vol. 224(1), pp. 39-41	DOI
Abstract: The magnetic susceptibility of UCu3Au2 and UCu3Au2 has been measured at 78 and 290 K under hydrostatic pressures up to 2 kbar. The pressure dependence of the susceptibility is correlated with the change in the paramagnetic Curie temperature. For both compounds the dΘ dP value was determined to be about -0.2±0.05 K kbar-1.
BibTeX: @article{Panfilov199539, author = {Panfilov, A.S. and Svechkarev, I.V. and Troć, R. and Tran, V.H.}, title = {Effect of pressure on magnetic susceptibility of UCu5-xAux alloys}, journal = {Journal of Alloys and Compounds}, year = {1995}, volume = {224}, number = {1}, pages = {39-41}, doi = {http://dx.doi.org/10.1016/0925-8388(94)01519-8} }
Pluzhnikov V., Czopnik A., Svechkarev I.	de Haas-van Alphen effect in ScGa3, LuGa3 and YIn3 [Abstract] [BibTeX]	1995	Physica B: Physics of Condensed Matter Vol. 212(4), pp. 375-378	DOI
Abstract: The angular dependencies of the de Haas-van Alphen (dHvA) frequencies and the corresponding cyclotron masses are determined for ScGa3, LuGa3, and YIn3 in the planes 100 and 110. The dHvA frequency branches for all three compounds are in the range from 2.3 × 106 Oe to 105 × 106 Oe. For all of them cyclotron masses are light; their values are between 0.2m0 and 0.8m0.
BibTeX: @article{Pluzhnikov1995375, author = {Pluzhnikov, V.B. and Czopnik, A. and Svechkarev, I.V.}, title = {de Haas-van Alphen effect in ScGa3, LuGa3 and YIn3}, journal = {Physica B: Physics of Condensed Matter}, year = {1995}, volume = {212}, number = {4}, pages = {375-378}, doi = {http://dx.doi.org/10.1016/0921-4526(95)00382-J} }
Zherlitsyn S., Fil V., Finsterbusch D., Molter J., Wolf B., Bruls G., Lüthi B., Barilo S., Zhigunov D.	High field phase diagram of Nd2-xCexCuO4 single crystals [Abstract] [BibTeX]	1995	Physica B: Physics of Condensed Matter Vol. 211(1-4), pp. 168-171	DOI
Abstract: We present high magnetic field ultrasonic and magnetic susceptibility measurements for Nd2CuO4 and Nd1.85Ce0.15CuO4 single crystals at temperatures below 2 K. The magnetic field dependences of the c11, c66 acoustic modes and the magnetic susceptibility demonstrate a large number of field induced phase transitions which are reduced in the Ce-doped compound. Using the anomalies in the sound velocity and magnetic susceptibility we obtained the low temperature range of B-T phase diagrams of these compounds for magnetic field applied along the [100] direction.
BibTeX: @article{Zherlitsyn1995168, author = {Zherlitsyn, S. and Fil, V.D. and Finsterbusch, D. and Molter, J. and Wolf, B. and Bruls, G. and Lüthi, B. and Barilo, S.N. and Zhigunov, D.I.}, title = {High field phase diagram of Nd2-xCexCuO4 single crystals}, journal = {Physica B: Physics of Condensed Matter}, year = {1995}, volume = {211}, number = {1-4}, pages = {168-171}, doi = {http://dx.doi.org/10.1016/0921-4526(94)00976-3} }
Desnenko V.A., Panfilov A.S., Smirnov A.I.	Effect of uniaxial pressure on magnetic-susceptibility of intermetallic compound CeAl2 [Abstract] [BibTeX]	1995	Fizika Nizkikh Temperatur Vol. 21(5), pp. 546-552	URL
Abstract: A SQUID magnetometer-based method is proposed to measure the effects of uniaxial pressure (up to 1-2 kbar) on the magnetic moment of solids in the temperature range 4.2-300 K. The method was used to study the magnetic susceptibility of the single crystal CeAl2 in the paramagnetic state. The results obtained show a strong uniaxial pressure effect and its high anisotropy for various magnetic field directions with respect to the stress.
BibTeX: @article{desnenko1995, author = {Desnenko, V. A. and Panfilov, A. S. and Smirnov, A. I.}, title = {Effect of uniaxial pressure on magnetic-susceptibility of intermetallic compound CeAl2}, journal = {Fizika Nizkikh Temperatur}, publisher = {FIZIKA NIZKIKH TEMPERATUR}, year = {1995}, volume = {21}, number = {5}, pages = {546-552}, url = {https://inis.iaea.org/search/search.aspx?orig_q=RN:27043547} }
Grechnev G.E., Svechkarev I.V., Fomenko Y.V., Hjelm A.	Electronic structure of intermetallic compounds HoIn3 and TmGa3 [Abstract] [BibTeX]	1995	Fizika Nizkikh Temperatur Vol. 21(3), pp. 333-335	URL
Abstract: The first ab initio calculations of the spin-polarized electronic structure are carried out for heavy rare-earth metal compounds HoIn3 and TmGa3. The topology of the Fermi surface is determined for these compounds. The site- and angular-momentum-resolved contributions to the total magnetic moments are found for f and sp atoms.
BibTeX: @article{grechnev1995, author = {Grechnev, G. E. and Svechkarev, I. V. and Fomenko, Yu. V. and Hjelm, A.}, title = {Electronic structure of intermetallic compounds HoIn3 and TmGa3}, journal = {Fizika Nizkikh Temperatur}, year = {1995}, volume = {21}, number = {3}, pages = {333-335}, url = {http://fnte.ilt.kharkov.ua/fnt/pdf/21/21-3/f21-0333r.pdf} }
Fil V., Bezugly E., Burma N., Kolobov I., Vitebsky I., Knigavko A., Lavrinenko N., Barilo S., Zhigunov D., Soshnikov L.	Giant anisotropy of elastic moduli of La2CuO4 single crystals in (001) plane [Abstract] [BibTeX]	1994	Physica C: Superconductivity and its applications Vol. 235-240(PART 2), pp. 1215-1216	DOI
Abstract: Sound velocities of a practically untwinned orthorhombic crystal of La2CuO4 are measured. The procedure for the calculation of elastic moduli in a twinned sample from the untwinned crystal dates is developed. In La1.87Sr0.13CuO4 single changes of elastic moduli under the tetragonal to orthorhombic structural phase transition are measured.
BibTeX: @article{Fil19941215, author = {Fil, V.D. and Bezugly, E.V. and Burma, N.G. and Kolobov, I.G. and Vitebsky, I.M. and Knigavko, A.N. and Lavrinenko, N.M. and Barilo, S.N. and Zhigunov, D.I. and Soshnikov, L.E.}, title = {Giant anisotropy of elastic moduli of La2CuO4 single crystals in (001) plane}, journal = {Physica C: Superconductivity and its applications}, year = {1994}, volume = {235-240}, number = {PART 2}, pages = {1215-1216}, doi = {http://dx.doi.org/10.1016/0921-4534(94)91832-5} }
Grechnev G., Jarlborg T., Panfilov A., Peter M., Svechkarev I.	The effect of pressure on the electronic structure and magnetic susceptibility of ε-FeSi [Abstract] [BibTeX]	1994	Solid State Communications Vol. 91(10), pp. 835-838	DOI
Abstract: The pressure effect on the magnetic susceptibility of FeSi has been studied in the temperature range 78-300 K. Assuming the leading role of the gap value Eg as the energy parameter in this range the value dln Eg/dln V = -6 was evaluated. The electronic structure of FeSi was determined using the local spin-density functional approximation and the LMTO method to solve the band structure problem self-consistently. The obtained fine structure of the density of states near the gap differs from the DOS curve for MnSi. The stability of monosilicides is discussed by considering the bonding origin of electronic states near the Fermi energy. The calculated derivative dln Eg/dln V = -5.9 is in agreement with the experimental one.
BibTeX: @article{Grechnev1994835, author = {Grechnev, G.E. and Jarlborg, T. and Panfilov, A.S. and Peter, M. and Svechkarev, I.V.}, title = {The effect of pressure on the electronic structure and magnetic susceptibility of ε-FeSi}, journal = {Solid State Communications}, year = {1994}, volume = {91}, number = {10}, pages = {835-838}, doi = {http://dx.doi.org/10.1016/0038-1098(94)90659-9} }
Kolobov I., Fil V., Fil D., Barilo S., Zhigunov D.	Possible evidence of the existence of a soundlike collective mode in Nd2-xCexCuO4 [Abstract] [BibTeX]	1994	Physical Review B Vol. 49(1), pp. 744-747	DOI
Abstract: Sound velocities along high- and low-symmetry directions are measured with the goal of determining the full set of elastic constants in Nd2-xCexCuO4. The velocity of quasitransverse mode (vt) with wave vectors q lying in the 010 plane shows anomalous behavior. Rotating q from the [100] to the [001] direction we registered, first, a strong lowering, and, then, a steplike increase (up to two times) of vt. There is no reasonable explanation of the observed peculiarities in the framework of conventional elasticity theory and the effect can be accounted for by the existence of a two-dimensional soundlike collective mode of electronic origin that strongly interacts with lattice vibrations. A proposed phenomenological model of the effect is in qualitative agreement with the experimental data.
BibTeX: @article{Kolobov1994744, author = {Kolobov, I.G. and Fil, V.D. and Fil, D.V. and Barilo, S.N. and Zhigunov, D.I.}, title = {Possible evidence of the existence of a soundlike collective mode in Nd2-xCexCuO4}, journal = {Physical Review B}, year = {1994}, volume = {49}, number = {1}, pages = {744-747}, doi = {http://dx.doi.org/10.1103/PhysRevB.49.744} }
Czopnik A., Panfilov A.S., Svechkarev I.V.	Pressure effect on magnetic susceptibility of SmIn3 and DyIn3 [Abstract] [BibTeX]	1994	Fizika Nizkikh Temperatur Vol. 20(1), pp. 48-50	URL
Abstract: Pressure dependence of magnetic susceptibility of SmIn3 and DyIn3 compounds up to 2 kbar was measured at 78 and 295 K. Results are discussed in the framework of Van Vleck theory with taking into account the exchange interaction f and the Sm3+ ion ground state splitting DELTA by the crystalline electric field. Supposing the value of d ln I/d In V = - 2.8, which was found in DyIn3, the same in both compounds, the derivatives with respect to volume d ln DELTA/d ln V = - 6.7 and d ln chi(d)d/d In Y = 1.9 in SmIn3 are obtained. The scale of d-band contribution chi(d) into SmIn3 susceptibility is close to one in DyIn3.
BibTeX: @article{czopnik1994, author = {Czopnik, A. and Panfilov, A. S. and Svechkarev, I. V.}, title = {Pressure effect on magnetic susceptibility of SmIn3 and DyIn3}, journal = {Fizika Nizkikh Temperatur}, publisher = {FIZIKA NIZKIKH TEMPERATUR}, year = {1994}, volume = {20}, number = {1}, pages = {48-50}, url = {https://inis.iaea.org/search/search.aspx?orig_q=RN:25071904} }
Bezuglyi E., Burma N., Deyneka E., Kopeliovich A., Fil V.	Investigation of low-temperature electron relaxation by zero sound attenuation [Abstract] [BibTeX]	1993	Journal of Low Temperature Physics Vol. 91(3-4), pp. 179-202	DOI
Abstract: We develop a new method of investigation of low-temperature electron relaxation in metals, based on the analysis of the temperature dependences of the attenuation of zero sound excited by ultrasonic pulses. We have discovered that these dependences obtained in the temperature region about of 1-8 K reproduce directly the temperature behavior of the electron scattering rate. The main features of our method are its insensitivity to small-angle scattering and the additivity of contributions of various relaxation processes to the total scattering rate. Both the theoretical analysis of zero-sound propagation in various damping regimes and special experiments produced for gallium confirm the validity of our consideration. We have identified the considerable contribution of electron-electron collisions in all investigated metals (gallium, aluminum, molybdenum, and tungsten) in the whole studied temperature interval and established the dominating role of Umklapp processes in the zero-sound damping at T >- 4 K for gallium and most probably for tungsten. We interpret the latter result as the first experimental observation of Peierls' exponent in polyvalent metals in zero magnetic field. The values obtained for electron-electron and electron-phonon scattering rates are compared with known experimental data and theoretical estimations.
BibTeX: @article{Bezuglyi1993179, author = {Bezuglyi, E.V. and Burma, N.G. and Deyneka, E.Yu. and Kopeliovich, A.I. and Fil, V.D.}, title = {Investigation of low-temperature electron relaxation by zero sound attenuation}, journal = {Journal of Low Temperature Physics}, publisher = {Kluwer Academic Publishers}, year = {1993}, volume = {91}, number = {3-4}, pages = {179-202}, doi = {http://dx.doi.org/10.1007/BF00120848} }
Panfilov A.S., Svechkarev I.V., Fawcett E.	The magnetovolume effect in CeAl2 [Abstract] [BibTeX]	1993	International Journal of Modern Physics B Vol. 07(01n03), pp. 703-707	DOI
Abstract: The magnetic susceptibility of CeAl2 was measured under pressure up to 2 kbar at 78, 185 and 296 K. The results are treated in terms of a theory which includes the Kondo effect and crystal field splitting. The derivatives with respect to volume are obtained for the splitting ∆ and the effective sd-f exchange parameter I.
BibTeX: @article{panfilov1993, author = {Panfilov, A. S. and Svechkarev, I. V. and Fawcett, E.}, title = {The magnetovolume effect in CeAl2}, journal = {International Journal of Modern Physics B}, year = {1993}, volume = {07}, number = {01n03}, pages = {703-707}, doi = {http://dx.doi.org/10.1142/S0217979293001487} }
Panfilov A.S., Svechkarev I.V.	The magnetovolume effect in strong itinerant paramagnets [Abstract] [BibTeX]	1993	International Journal of Modern Physics B Vol. 07(01n03), pp. 699-702	DOI
Abstract: The results of investigations of the enhanced spin susceptibility of some transition metals and alloys under pressure are reviewed and discussed. The evaluated values of the volume derivative of the interaction parameter d In J/d In V unambiguously confirm the predominant role of the short-range electron correlations in these systems.
BibTeX: @article{panfilov1993ii, author = {Panfilov, A. S. and Svechkarev, I. V.}, title = {The magnetovolume effect in strong itinerant paramagnets}, journal = {International Journal of Modern Physics B}, year = {1993}, volume = {07}, number = {01n03}, pages = {699-702}, doi = {http://dx.doi.org/10.1142/S0217979293001475} }
Panfilov A.S., Pushkar Y.Y., Svechkarev I.V.	Effect of pressure on magnetic susceptibility of CeB6 [Abstract] [BibTeX]	1993	Fizika Nizkikh Temperatur Vol. 19(1), pp. 96-98	URL
Abstract: The effect of uniform compression on magnetic susceptibility of CeB6 has been investigated at 20,4; 78 and 296 K. The results are analysed in the context of the theory including the joint influence of the Kondo effect and the crystalline field on susceptibility. The dependences of the microscopic characteristic of the, system, viz. the multiplet splitting of 2F(5/2) by the crystalline field and the Kondo interaction parameter, on the atomic volume have been obtained.
BibTeX: @article{panfilov1993iii, author = {Panfilov, A. S. and Pushkar, Y. Y. and Svechkarev, I. V.}, title = {Effect of pressure on magnetic susceptibility of CeB6}, journal = {Fizika Nizkikh Temperatur}, publisher = {FIZIKA NIZKIKH TEMPERATUR}, year = {1993}, volume = {19}, number = {1}, pages = {96-98}, url = {http://fnt.ilt.kharkov.ua/fnt/pdf/19/19-1/f19-0096r.pdf} }
Panfilov A.S., Svechkarev I.V., Romasheva L.F.	The effect of pressure on paramagnetic susceptibility of Fe1-xCoxSi alloys [Abstract] [BibTeX]	1993	Fizika Nizkikh Temperatur Vol. 19(3), pp. 284-288	URL
Abstract: The effect of pressure up to 4 kbar on paramagnetic susceptibility of quasi-binary solid solutions of Fe1-xCoxSi (0 less-than-or-equal-to x less-than-or-equal-to 0.7) is studied at temperatures of 78 and 293 K. The derivative of the parameter of effective electron interaction with respect lo the volume in the Stoner enhancement of paramagnetism is found to be d ln I/d ln V = -1.3+/-0.15 indicating a considerable role of the electron correlations in this system.
BibTeX: @article{panfilov1993iv, author = {Panfilov, A. S. and Svechkarev, I. V. and Romasheva, L. F.}, title = {The effect of pressure on paramagnetic susceptibility of Fe1-xCoxSi alloys}, journal = {Fizika Nizkikh Temperatur}, publisher = {FIZIKA NIZKIKH TEMPERATUR}, year = {1993}, volume = {19}, number = {3}, pages = {284-288}, url = {http://fnt.ilt.kharkov.ua/fnt/pdf/19/19-3/f19-0284r.pdf} }
Zvyagina G., Fil V., Kolobov I., Zherlitsyn S., Vitebskii I.	Acoustic properties of KSc(MoO4)2 in the vicinity of structural phase transition [Abstract] [BibTeX]	1992	Ferroelectrics Vol. 130(4), pp. 315-320	URL
Abstract: The changes of the sound velocity and attenuation of the acoustic modes, corresponding to the C11, C33, C44 and C66 elastic moduli of a trigonal crystal KSc(MoO4)2 in the vicinity of improper ferroelastic second-order phase transition (T1 ≈ 260 K) are studied. All of these moduli are characterized by a jump-like decrease below T1, anomalously large (to 50 percent) for the oscillations whose displacement vectors are in the basal plane. The X-ray results of the KSc(MoO4)2 single crystals permit an assumption that D3d 3 → C2h 3 is a more probable phase transition scheme.
BibTeX: @conference{Zvyagina1992315, author = {Zvyagina, G.A. and Fil, V.D. and Kolobov, I.G. and Zherlitsyn, S.V. and Vitebskii, I.M.}, title = {Acoustic properties of KSc(MoO4)2 in the vicinity of structural phase transition}, journal = {Ferroelectrics}, year = {1992}, volume = {130}, number = {4}, pages = {315-320}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0027036191&partnerID=40&md5=ce1302dca901f365ab55150ab8853001} }
Burma N.G., Gaiduk A.L., Zherlitsyn S.V., Kolobov I.G., Fil V.D., Panfilov A.S., Svechkarev I.V., Ges A.D., Barilo S.N., Zhigunov D.I.	Elastic and magnetic-properties of single-crystals La2CuO4-delta [Abstract] [BibTeX]	1992	Fizika Nizkikh Temperatur Vol. 18(3), pp. 247-254	URL
Abstract: The absolute sound velocities are measured in the single crystals La2CuO4, which are used as a basis for the assumption of the existence of monoclinic distortions in the La2CuO4 lattice. The twin-structure-averaged components of the elastic moduli tensor are found. An anomalous softening of the moduli c11 and (c11 - c12)/2 is revealed that is correlated with the magnetic susceptibility behavior.
BibTeX: @article{burma1992, author = {Burma, N. G. and Gaiduk, A. L. and Zherlitsyn, S. V. and Kolobov, I. G. and Fil, V. D. and Panfilov, A. S. and Svechkarev, I. V. and Ges, A. D. and Barilo, S. N. and Zhigunov, D. I.}, title = {Elastic and magnetic-properties of single-crystals La2CuO4-delta}, journal = {Fizika Nizkikh Temperatur}, publisher = {FIZIKA NIZKIKH TEMPERATUR}, year = {1992}, volume = {18}, number = {3}, pages = {247-254}, url = {https://inis.iaea.org/search/search.aspx?orig_q=RN:24071595} }
Panfilov A.S., Svechkarev I.V., Skolozdra R.V., Smirnov A.I.	Influence of all-round compression on magnetic susceptibility of RECu intermetallics (RE = Dy, Ho, Tm) [BibTeX]	1992	Fizika Metallov i Metallovedenie Vol. 73*(5), pp. 20-24	URL
BibTeX: @article{panfilov1992, author = {Panfilov, A. S. and Svechkarev, I. V. and Skolozdra, R. V. and Smirnov, A. I.}, title = {Influence of all-round compression on magnetic susceptibility of RECu intermetallics (RE = Dy, Ho, Tm)}, journal = {Fizika Metallov i Metallovedenie}, publisher = {GOSUDARSTVENNOE NAUCHNO-TEKH}, year = {1992}, volume = {73*}, number = {5}, pages = {20-24}, url = {http://impo.imp.uran.ru/fmm/Electron/vol73_5/abstract3.html} }
Chiang Y.N., Shevchenko O.G., Panfilov A.S.	Thermopower and fluctuation effects in HTSC crystals of Bismuth cuprates [Abstract] [BibTeX]	1992	Fizika Nizkikh Temperatur Vol. 18(12), pp. 1315-1323	URL
Abstract: Thermopower, conductivity and magnetic susceptibility of HTSC bismuth curpate crystals with the same stoichiometry Bi2Sr2CaCu2Ox are investigated. In the vicinity of the superconducting transition temperature (almost-equal-to 10% T(c) in width) the thermopower temperature dependence turns out to have a peak-shaped peculiarity as well as different behaviours for various samples beyond the peak. These features are closely associated with the defect (impurity) content in the samples. We explain the observed phenomena using ideas of thermodynamic Gauss fluctuations of the two-component order parameter, 2D/0D crossover for two-band superconductor with a narrow band near the Fermi level overlapping a wide band.
BibTeX: @article{panfilov1992ii, author = {Chiang, Y. N. and Shevchenko, O. G. and Panfilov, A. S.}, title = {Thermopower and fluctuation effects in HTSC crystals of Bismuth cuprates}, journal = {Fizika Nizkikh Temperatur}, publisher = {FIZIKA NIZKIKH TEMPERATUR}, year = {1992}, volume = {18}, number = {12}, pages = {1315-1323}, url = {http://fnt.ilt.kharkov.ua/fnt/pdf/18/18-12/f18-1315r.pdf} }
Khotkevich V.V., Grechnev G.E.	Electronic-structure of intermetallic compounds in Cd-Mg system [Abstract] [BibTeX]	1992	Fizika Nizkikh Temperatur Vol. 18(8), pp. 880-888	URL
Abstract: The electron structure of isostructural hexagonal crystals of Cd3Mg and Mg3Cd compounds is studied. The electron energy spectra are calculated using the method of pseudopotential. A detailed structure of the electron density of states and the Fermi surface of Cd3Mg and Mg3Cd is found. It is shown that the one-electron component of the total energy of the crystal predominates in the stabilization of the ordered state at low temperature. The calculated Fermi surface characteristics of the ordered compound Cd3Mg are compared with experimental result on the de Haas - van Alphen effect and a new interpretation of the frequency oscillations observed experimentally is proposed.
BibTeX: @article{khotkevich1992, author = {Khotkevich, V. V. and Grechnev, G. E.}, title = {Electronic-structure of intermetallic compounds in Cd-Mg system}, journal = {Fizika Nizkikh Temperatur}, publisher = {FIZIKA NIZKIKH TEMPERATUR}, year = {1992}, volume = {18}, number = {8}, pages = {880-888}, url = {https://inis.iaea.org/search/searchsinglerecord.aspx?recordsFor=SingleRecord&RN=25020215} }
Bezuglyi E., Burma N., Deineka E., Fil' V.	Zero sound in metals [Abstract] [BibTeX]	1991	Physica B: Physics of Condensed Matter Vol. 173(4), pp. 405-407	DOI
Abstract: The excitation of the zero sound (ZS) by means of an elastic wave in pure gallium has been realized. The influence of temperature alternating, superconducting transition and magnetic fields on ZS are studied. The results are discussed in terms of a simple model of a compensated metal with two spherical Fermi surfaces.
BibTeX: @article{Bezuglyi1991405, author = {Bezuglyi, E.V. and Burma, N.G. and Deineka, E.Yu. and Fil', V.D.}, title = {Zero sound in metals}, journal = {Physica B: Physics of Condensed Matter}, year = {1991}, volume = {173}, number = {4}, pages = {405-407}, doi = {http://dx.doi.org/10.1016/0921-4526(91)90471-P} }
Bezuglyi E., Burma N., Deineka E., Fil' V., Kaufmann H.-J.	Zero sound in normal and superconducting molybdenum [Abstract] [BibTeX]	1991	Journal of Physics: Condensed Matter Vol. 3(40), pp. 7867-7876	DOI
Abstract: The authors discuss the physical nature of electron sound signals excited in molybdenum by an acoustic wave and propagating at the Fermi velocity. The experimental temperature dependences of the amplitude and the phase velocity of these signals have been studied in the normal and superconducting state. They interpret this effect observed earlier in Ga by Burma et al. as the excitation of a weakly damped zero-sound wave caused by the Fermi-liquid interaction between charge carriers. A dominating role of the electron-electron collisions in the zero-sound damping in Mo was established, and the corresponding relaxation time was estimated. Theoretical calculations of the expected zero-sound behaviour in a superconductor are in good agreement with the experimental data and enable them to determine the intensity of the Fermi-liquid interaction.
BibTeX: @article{Bezuglyi19917867, author = {Bezuglyi, E.V. and Burma, N.G. and Deineka, E.Yu. and Fil', V.D. and Kaufmann, H.-J.}, title = {Zero sound in normal and superconducting molybdenum}, journal = {Journal of Physics: Condensed Matter}, year = {1991}, volume = {3}, number = {40}, pages = {7867-7876}, doi = {http://dx.doi.org/10.1088/0953-8984/3/40/008} }
Fawcett E., Pluzhnikov V., Klimker H.	Thermal expansion and magnetostriction of CeAl2 [Abstract] [BibTeX]	1991	Physical Review B Vol. 43(10), pp. 8531-8538	DOI
Abstract: The thermal expansion and magnetostriction for various configurations of strain and field direction in single crystals of CeAl2 are measured in the temperature range 1.2 to 4.2 K in magnetic fields up to 10 T. A phase diagram is constructed, comprising the antiferromagnetic and high-field phases. The temperature dependence of the magnetostriction constants is determined for the high-field phase in a field of 10 T relative to the zero-field antiferromagnetic state. The paramagnetostriction coefficients are measured at a temperature of 4.2 K in fields up to 5 T.
BibTeX: @article{Fawcett19918531, author = {Fawcett, E. and Pluzhnikov, V. and Klimker, H.}, title = {Thermal expansion and magnetostriction of CeAl2}, journal = {Physical Review B}, year = {1991}, volume = {43}, number = {10}, pages = {8531-8538}, doi = {http://dx.doi.org/10.1103/PhysRevB.43.8531} }
Grechnev G., Kubler J., Svechkarev I.	Itinerant magnetism and electronic properties of FeGe2 [Abstract] [BibTeX]	1991	Journal of Physics: Condensed Matter Vol. 3(37), pp. 7199-7206	DOI
Abstract: The electronic and magnetic structure of tetragonal FeGe2 is determined using the local spin-density functional approximation and the ASW method to solve the band-structure problem self-consistently. The calculations reveal that the collinear antiferromagnetic structure-in contrast to a non-collinear one-has the lowest total energy and seems the most preferable candidate for the low-temperature ground-state phase of FeGe2 in agreement with recent neutron diffraction experiments. The calculated Fermi surface cross-sections and cyclotron masses are in good agreement with the DHVA experimental data. From the DHVA and heat capacity data together with the results of band structure calculations the average value of the electron-phonon interaction constant lambda equivalent to 0.5 has been deduced for FeGe 2. For the alternative non-collinear model the authors obtained a higher value of the total energy and poor agreement with the DHVA experiment.
BibTeX: @article{Grechnev19917199, author = {Grechnev, G.E. and Kubler, J. and Svechkarev, I.V.}, title = {Itinerant magnetism and electronic properties of FeGe2}, journal = {Journal of Physics: Condensed Matter}, year = {1991}, volume = {3}, number = {37}, pages = {7199-7206}, doi = {http://dx.doi.org/10.1088/0953-8984/3/37/012} }
Panfilov A.S., Smirnov A.I., Kuzmicheva L.B.	Fluctuation diamagnetism in high-Tc superconductors at T>Tc [BibTeX]	1991	Fizika Nizkikh Temperatur Vol. 17(9), pp. 1152-1156	URL
BibTeX: @article{panfilov1991, author = {Panfilov, A. S. and Smirnov, A. I. and Kuzmicheva, L. B.}, title = {Fluctuation diamagnetism in high-Tc superconductors at T>Tc}, journal = {Fizika Nizkikh Temperatur}, publisher = {FIZIKA NIZKIKH TEMPERATUR}, year = {1991}, volume = {17}, number = {9}, pages = {1152-1156}, note = {1st International Conf On Strongly Correlated Electron States In Condensed Media, Crimea, USSR, Apr 29-may 01, 1991}, url = {http://fnt.ilt.kharkov.ua/fnt/pdf/17/17-9/f17-1152e.pdf} }
Grechnev G.E., Kvachantiradze G.G., Papuashvili N.A., Kharebov K.S.	Induced polymorphous transformations of molybdenum under carbon and nitrogen implantation [Abstract] [BibTeX]	1991	Zhurnal Tekhnicheskoj Fiziki Vol. 61(2), pp. 93-97	URL
Abstract: Possibility of induced polymorphous transformations of molybdenum by carbon and nitrogen implantation with formation of heterophase systemns Mo-MoC, Mo-Mo is indicated. Heterophase system free energies for different structural states of crystal matrix are calculated. Carbon and nitrogen criterial concentrations necessary critical concentrations necessary for molybdenum polymorphous transformations are identified.
BibTeX: @article{grechnev1991, author = {Grechnev, G. E. and Kvachantiradze, G. G. and Papuashvili, N. A. and Kharebov, K. S.}, title = {Induced polymorphous transformations of molybdenum under carbon and nitrogen implantation}, journal = {Zhurnal Tekhnicheskoj Fiziki}, year = {1991}, volume = {61}, number = {2}, pages = {93-97}, url = {https://inis.iaea.org/search/search.aspx?orig_q=RN:24035055} }
Savchenko N.V., Grechnev G.E., Svechkarev I.V.	Anisotropy of conduction electron g-factors in bcc transition metals - vanadium, niobium and tantalum [Abstract] [BibTeX]	1991	Fizika Nizkikh Temperatur Vol. 17(7), pp. 859-871	URL
Abstract: The Zeeman splitting for conduction electrons in d-metals such as vanadium, niobium, tantalum is studied theoretically by the RLMTO method. The results are presented, which were obtained from calculation and averaging of g-factors, from the analysis of their stability against variations of the number of states and from calculation of the Zeeman level splitting enhancement due to the electron-electron interaction. The orbit averaged g-factors are found to dislplay the anisotropic behaviour on 02 sheet of the Fermi surface in these metals. The calculated results are compared with experimental one and those obtained by other authors. Common trendes of the g-factor behaviour are formulated for all transition d-metals with cubic structure.
BibTeX: @article{savchenko1991, author = {Savchenko, N. V. and Grechnev, G. E. and Svechkarev, I. V.}, title = {Anisotropy of conduction electron g-factors in bcc transition metals - vanadium, niobium and tantalum}, journal = {Fizika Nizkikh Temperatur}, year = {1991}, volume = {17}, number = {7}, pages = {859-871}, url = {https://inis.iaea.org/search/searchsinglerecord.aspx?recordsFor=SingleRecord&RN=23069882} }
Zvyagina G., Zherlitsyn S., Fil V., Gurskas A.	Elastic properties of csdy1-xgdk(eu)x(moo4)2 in the region of structural phase transitions [Abstract] [BibTeX]	1990	Ferroelectrics Vol. 110(1), pp. 35-39	DOI
Abstract: An investigation is made of the temperature dependences of relative changes in the sound velocities and dielectric permeability along the principle axes of CsDy, xGd(Eu)x(Mo04)2 system crystals in the region of second-order structural phase transitions. The absence of noticeable softening of the transverse moduli points to the antiferroelastic type of transition. One more first-order structural transition is detected in the temperature range 24 to 32 K.
BibTeX: @article{Zvyagina199035, author = {Zvyagina, G.A. and Zherlitsyn, S.V. and Fil, V.D. and Gurskas, A.A.}, title = {Elastic properties of csdy1-xgdk(eu)x(moo4)2 in the region of structural phase transitions}, journal = {Ferroelectrics}, year = {1990}, volume = {110}, number = {1}, pages = {35-39}, doi = {http://dx.doi.org/10.1080/00150199008015286} }
Mikitik G.P., Panfilov A.S.	Estimation of upper critical-field derivative with respect to temperature and its anisotropy for high-Tc superconductors by using fluctuation effects in thermal capacity and magnetic susceptibility [Abstract] [BibTeX]	1990	Fizika Nizkikh Temperatur Vol. 16(6), pp. 794-798	URL
Abstract: A method based on the analysis of fluctuation contributions to thermal capacity and magnetic susceptibility is proposed to estimate the upper critical derivatives with respect to temperature for high-Tc superconductors. The fluctuaton contribution to magnetic susceptibility of YBa2Cu3O7 is measured, and the above derivatives for this superconductor are evaluated.
BibTeX: @article{mikitik1990, author = {Mikitik, G. P. and Panfilov, A. S.}, title = {Estimation of upper critical-field derivative with respect to temperature and its anisotropy for high-Tc superconductors by using fluctuation effects in thermal capacity and magnetic susceptibility}, journal = {Fizika Nizkikh Temperatur}, publisher = {FIZIKA NIZKIKH TEMPERATUR}, year = {1990}, volume = {16}, number = {6}, pages = {794-798}, url = {https://inis.iaea.org/search/search.aspx?orig_q=RN:23034450} }
Obolenskii M.A., Bondarenko A.V., Beletskii V.I., Morgun V.N., Popov V.N., Chebotaev N.N., Svechkarev I.V., Panfilov A.S., Smirnov A.A., Mironov O.A., Chistyakov S.V., Skrilev I.Y.	Carrier transfer kinetics, phase transition and fluctuation-enhanced phenomena in YBa2Cu3Ox [Abstract] [BibTeX]	1990	Fizika Nizkikh Temperatur Vol. 16(5), pp. 574-577	URL
Abstract: The temperature dependences of electrical resistivity, thermoelectric power, magnetic susceptibility, thermal expansion coefficient, upper and lower critical fields, and critical currents in single crystals of Y1Ba2Cu3O(x) (x = 6, 9) and the temperature dependences of the Young modulus and internal friction in melt samples of Y1Ba2Cu3O(x) were measured. The results obtained show that Y1Ba2CuO3 undergoes a phase transition at 50, 150, and 220 K which influences both electron and lattice characteristics. The observed temperature dependences of electrical resistivity and magnetic susceptibility indicate the fluctuation of carriers above the critical temperature. The measured results are in good agreement with Aslamazov-Larkin theory.
BibTeX: @article{obolenskii1990, author = {Obolenskii, M. A. and Bondarenko, A. V. and Beletskii, V. I. and Morgun, V. N. and Popov, V. N. and Chebotaev, N. N. and Svechkarev, I. V. and Panfilov, A. S. and Smirnov, A. A. and Mironov, O. A. and Chistyakov, S. V. and Skrilev, I. Y.}, title = {Carrier transfer kinetics, phase transition and fluctuation-enhanced phenomena in YBa2Cu3Ox}, journal = {Fizika Nizkikh Temperatur}, publisher = {FIZIKA NIZKIKH TEMPERATUR}, year = {1990}, volume = {16}, number = {5}, pages = {574-577}, url = {http://fnt.ilt.kharkov.ua/fnt/pdf/16/16-5/f16-0574e.pdf} }
Obolenskii M.A., Bondarenko A.V., Beletskii V.I., Morgun V.N., Popov V.P., Chebotaev N.N., Panfilov A.S., Smirnov A.I., Mironov O.A., Chistyakov S.V., Skrylev I.Y.	Synthesis and physical properties of YBa2Cu3O7 single-crystals [Abstract] [BibTeX]	1990	Fizika Nizkikh Temperatur Vol. 16(9), pp. 1103-1127	URL
Abstract: The growth of YBa2Cu307 single crystals on melting surface under gradient condictions is described. The properties of the single crystals in normal and superconducting states are comprehensively studied. The experimental results suggest that a martensite-type phase transition occurs in the temperature region of 200 to 230 K. It is shown that the elastic properties and the thermal expansion coefficient of the ceramic samples are controlled by thermal activation processes. Fluctuation contribution to electrical conductivity and magretic susceptibility are estimated by temperature dependences of both electrical resistivity and magnetic susceptibility anisotropy of the single crystals.
BibTeX: @article{obolenskii1990ii, author = {Obolenskii, M. A. and Bondarenko, A. V. and Beletskii, V. I. and Morgun, V. N. and Popov, V. P. and Chebotaev, N. N. and Panfilov, A. S. and Smirnov, A. I. and Mironov, O. A. and Chistyakov, S. V. and Skrylev, I. Y.}, title = {Synthesis and physical properties of YBa2Cu3O7 single-crystals}, journal = {Fizika Nizkikh Temperatur}, publisher = {FIZIKA NIZKIKH TEMPERATUR}, year = {1990}, volume = {16}, number = {9}, pages = {1103-1127}, url = {https://inis.iaea.org/search/search.aspx?orig_q=RN:23042040} }
Panfilov A.S., Svechkarev I.V., Smirnov A.I., Diko P., Mihalik M., Tima T., Zentko A.	Magnetic properties of U2Zn17 compound [Abstract] [BibTeX]	1990	Fizika Nizkikh Temperatur Vol. 16(8), pp. 1039-1042	URL
Abstract: Magnetic susceptibility of polycrystal samples of a heavy-fermion U2Zn17 compound is measured in a 0,5 mT - 1 T magnetic field range at temperatures 1.7-300 K. The values of parameters of modified Curie-Weiss law which the susceptibility is subjected to at T>40 K are ascertained. One cannot observe any effect to superconductivity caused by deviations from stochiometry and the existence of accompaning phases. The known low-temperature characteristic features of susceptibility can be attributed to antiferromagnetic order in U2Zn17 at T=10K.
BibTeX: @article{panfilov1990, author = {Panfilov, A. S. and Svechkarev, I. V. and Smirnov, A. I. and Diko, P. and Mihalik, M. and Tima, T. and Zentko, A.}, title = {Magnetic properties of U2Zn17 compound}, journal = {Fizika Nizkikh Temperatur}, publisher = {FIZIKA NIZKIKH TEMPERATUR}, year = {1990}, volume = {16}, number = {8}, pages = {1039-1042}, url = {https://inis.iaea.org/search/search.aspx?orig_q=RN:23034128} }
Zvyagin A.I., Stepanov A.A., Pashchenko V.A., Kobets M.I., Panfilov A.S., Barilo S.N., Zhigunov D.I.	Detection of low-frequency AFMR mode gap and magnetic phase transitions in Gd2CuO4 [Abstract] [BibTeX]	1990	Fizika Nizkikh Temperatur Vol. 16(11), pp. 1453-1458	URL
Abstract: Resonance and magnetic measurements of Gd2CuO4 singl crystals were made at low temperature including the region of magnetic ordering of the gadolinium subsystem. It is found that there is a gap in the low-frequency AFMR mode 0(10)/2-pi congruent-to 10 GHz (T = = 4.2 K) and the magnetic structure of Gd2CuO4 in weak magnetic fields experiences an orientation phase transition (H(c) congruent-to 3.5 kOe according to AFMR data; H(c1) congruent-to 2 kOe, H(c2) congruent-to 5.5 kOe according to magnetic measurements data for different magnetic field orientations in the plane (a, b)).
BibTeX: @article{zvyagin1990, author = {Zvyagin, A. I. and Stepanov, A. A. and Pashchenko, V. A. and Kobets, M. I. and Panfilov, A. S. and Barilo, S. N. and Zhigunov, D. I.}, title = {Detection of low-frequency AFMR mode gap and magnetic phase transitions in Gd2CuO4}, journal = {Fizika Nizkikh Temperatur}, publisher = {FIZIKA NIZKIKH TEMPERATUR}, year = {1990}, volume = {16}, number = {11}, pages = {1453-1458}, url = {https://inis.iaea.org/search/search.aspx?orig_q=RN:23034120} }
Desnenko V.A., Pecherskaya V.I., Fertman Y.L., Il'Ichev V.Y., Petsa P., Shtepan I.	Physicomechanical properties of a dispersion-hardening FeCrNi austenitic alloy [Abstract] [BibTeX]	1990	Physics of Metals and Metallography Vol. 70(3), pp. 89-93	URL
Abstract: An investigation is made of the magnetic susceptibility, electrical resistivity and microhardness of a commercial austenitic dispersion-hardening FeCrNi alloy. The Curie temperature of the alloy changes substantially after ageing. A combined analysis of the resistivity and microhardness results permits the ageing process to be described and the conclusion drawn that the change in chemical composition of the matrix as a result of dispersion hardening has a decisive influence on the magnetic state of the alloy.
BibTeX: @article{Desnenko199089, author = {Desnenko, V. A. and Pecherskaya, V. I. and Fertman, Ye. L. and Il'Ichev, V. Ya. and Petsa, P. and Shtepan, I.}, title = {Physicomechanical properties of a dispersion-hardening FeCrNi austenitic alloy}, journal = {Physics of Metals and Metallography}, year = {1990}, volume = {70}, number = {3}, pages = {89-93}, note = {cited By 0}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0025550936&partnerID=40&md5=06147c86367905c7b1d592d48051d2a0} }
Grechnev G.E., Ushakova N.V.	Band structure and stability of transition metal beryllides with CsCl structure [Abstract] [BibTeX]	1990	Metallofizika Vol. 12(2), pp. 6-10	URL
Abstract: Self-consistent calculations of electron structure of BeCo, BeNi, BeCu, BePb isostructural (CsCl) compounds are carried out by LMTO method in approximation of atomic spheres. In local approximation of electron density functional state equations derived from the first principles, equilibrium atomic volumes, bulk modulus and formation heats of these compounds as well as of a series of hypothetic Be compounds with other 3d-metals (with CsCl lattices) are obtained. The nature of stability of transition metal beryllides is discussed.
BibTeX: @article{grechnev1990, author = {Grechnev, G. E. and Ushakova, N. V.}, title = {Band structure and stability of transition metal beryllides with CsCl structure}, journal = {Metallofizika}, year = {1990}, volume = {12}, number = {2}, pages = {6-10}, url = {https://inis.iaea.org/search/search.aspx?orig_q=RN:23041709} }
Bakay A., Grechnev G., Kvachantiradze G., Svechkarev I.	On the polymorphous transformations induced in niobium as a result of carbon implantation [Abstract] [BibTeX]	1989	Physics of Metals and Metallography Vol. 67(5), pp. 37-41	URL
Abstract: It is shown that a polymorphous transformation can be induced in niobium as a result of carbon implantation. The critical carbon concentrations for such polymorphous transformations have been found with allowance for the free energy of the crystal lattice, energy of elastic stress fields and energies of interphase boundaries.
BibTeX: @article{Bakay198937, author = {Bakay, A.S. and Grechnev, G.Ye. and Kvachantiradze, G.G. and Svechkarev, I.V.}, title = {On the polymorphous transformations induced in niobium as a result of carbon implantation}, journal = {Physics of Metals and Metallography}, year = {1989}, volume = {67}, number = {5}, pages = {37-41}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0024776845&partnerID=40&md5=f9e1c904d0664f195ebe1a9e5e6c2ef3} }
Grechnev G., Savchenko N., Svechkarev I., Lee M., Perz J.	Conduction-electron g factors in the noble metals [Abstract] [BibTeX]	1989	Physical Review B Vol. 39(14), pp. 9865-9873	DOI
Abstract: The conduction-electron g factor has been calculated at points on the Fermi surfaces of copper, silver, and gold by a relativistic linearized muffin-tin orbital method in the atomic-sphere approximation. The orbital g factors for principal extremal orbits on the Fermi surface of each metal have been deduced. A comparison with experimental g-factor data makes it possible to estimate the exchange-correlation enhancement factor for electrons on the Fermi surface of copper. The Fermi-surface average of the enhancement factor is in agreement with the predictions of a first-principles calculation, and the data suggest a weak anisotropy. Experimental data for silver and gold prove to be insufficiently accurate to yield reliable values of the exchange-correlation enhancement factor. A g-factor anomaly on the neck orbit in gold is discussed.
BibTeX: @article{Grechnev19899865, author = {Grechnev, G.E. and Savchenko, N.V. and Svechkarev, I.V. and Lee, M.J.G. and Perz, J.M.}, title = {Conduction-electron g factors in the noble metals}, journal = {Physical Review B}, year = {1989}, volume = {39}, number = {14}, pages = {9865-9873}, doi = {http://dx.doi.org/10.1103/PhysRevB.39.9865} }
Svechkarev I.	Effect of pressure on the magnetic susceptibility of transition metals [Abstract] [BibTeX]	1989	Physica B: Physics of Condensed Matter Vol. 159(1), pp. 35-38	DOI
Abstract: The pressure effect on the magnetic susceptibility of electrons in metals of the sp-, d- and f-type is briefly discussed. The experimentally studied dependences of band spectrum and electron interaction parameters on the atomic volume are presented. The Hubbard model is found to be much better than the local density-functional approximation when describing the exchange-correlation enhancement behaviour of spin paramagnetism in d-metals. A probable cause of the observed paramagnetic moment sensitivity to pressure in the stable f-states of heavy rare-earth metals is considered.
BibTeX: @article{Svechkarev198935, author = {Svechkarev, I.V.}, title = {Effect of pressure on the magnetic susceptibility of transition metals}, journal = {Physica B: Physics of Condensed Matter}, year = {1989}, volume = {159}, number = {1}, pages = {35-38}, doi = {http://dx.doi.org/10.1016/S0921-4526(89)80049-3} }
Tarasenko V., Pluzhnikov V., Fawcett E.	Theory of the magnetic phase diagram and magnetostriction of FeGe2 [Abstract] [BibTeX]	1989	Physical Review B Vol. 40(1), pp. 471-478	DOI
Abstract: A Landau model based on the competition between quadratic and quartic exchange among moments in the four-sublattice structure of FeGe2 has been used to derive an expression for the free energy, and hence to determine the boundaries of the homogeneous antiferromagnetic (AF) phases in the phase diagram. Two types of AF spiral structure of different symmetry are found. The transverse AF spiral phase exists in comparatively small magnetic fields, H
BibTeX: @article{Tarasenko1989471, author = {Tarasenko, V.V. and Pluzhnikov, V. and Fawcett, E.}, title = {Theory of the magnetic phase diagram and magnetostriction of FeGe2}, journal = {Physical Review B}, year = {1989}, volume = {40}, number = {1}, pages = {471-478}, doi = {http://dx.doi.org/10.1103/PhysRevB.40.471} }
Panfilov A.S., Rybalko Y.I., Samovarov V.N., Svechkarev I.V., Smirnov A.I., Fugol I.Y.	Identification of superconductivity in La-Ba-Cu-O by luminescence spectra - comparison between optical and magnetic measurements [Abstract] [BibTeX]	1989	Fizika Nizkikh Temperatur Vol. 15(8), pp. 792-797	URL
Abstract: Comparative measurements of emission spectra, magnetic susceptibility and resistive characteristics of La-Ba-Cu-O samples are performed in the temperature range of 6 to 140 K. The impurity narrow-band emission line at 3.36 eV is shown to be sensitive to the phase transition points including the superconducting phase onset. The impurity emission spectra can be local optical probes to control electron and lattice changes in HTSCs.
BibTeX: @article{panfilov1989, author = {Panfilov, A. S. and Rybalko, Y. I. and Samovarov, V. N. and Svechkarev, I. V. and Smirnov, A. I. and Fugol, I. Y.}, title = {Identification of superconductivity in La-Ba-Cu-O by luminescence spectra - comparison between optical and magnetic measurements}, journal = {Fizika Nizkikh Temperatur}, publisher = {FIZIKA NIZKIKH TEMPERATUR}, year = {1989}, volume = {15}, number = {8}, pages = {792-797}, url = {https://inis.iaea.org/search/search.aspx?orig_q=RN:21078430} }
Dmitriev V.M., Panfilov A.S., Svechkarev I.V., Deineka T.G., Korshikova T.I., Ramakaeva R.F.	Evaluation of Hc2 for high-temperature superconductors RBa2Cu3O7 (R = Y, Gd, Tm, Yb) by the data on magnetization [Abstract] [BibTeX]	1989	Fizika Nizkikh Temperatur Vol. 15(9), pp. 998-1001	URL
Abstract: Using the data on magnetization of HTS ceramics RBa2Cu3O7, Hc2 at liquid nitrogen temperature is estimated by the standard expression for revercible magnetization of type II superconductors.
BibTeX: @article{panfilov1989ii, author = {Dmitriev, V. M. and Panfilov, A. S. and Svechkarev, I. V. and Deineka, T. G. and Korshikova, T. I. and Ramakaeva, R. F.}, title = {Evaluation of Hc2 for high-temperature superconductors RBa2Cu3O7 (R = Y, Gd, Tm, Yb) by the data on magnetization}, journal = {Fizika Nizkikh Temperatur}, publisher = {FIZIKA NIZKIKH TEMPERATUR}, year = {1989}, volume = {15}, number = {9}, pages = {998-1001}, url = {https://inis.iaea.org/search/search.aspx?orig_q=RN:21093086} }
Panfilov A.S., Pushkar Y.Y., Svechkarev I.V.	Effect of pressure on exchange-enhanced zone paramagnetism of palladium alloys [Abstract] [BibTeX]	1989	ZHURNAL EKSPERIMENTALNOI I TEORETICHESKOI FIZIKI Vol. 95(2), pp. 751-759	URL
Abstract: The influence of hydrostatic pressure at various temperatures on the magnetic susceptibility of palladium-based alloys characterized by high Stoner factors is investigated experimentally. The magnitude of the magnetovolumetric effect is investigated as a function of concentration and temperature using simple empirical models of the change in the electron spectrum under pressure and due to alloying within the framework of the band approach, and estimates of the volume integrals are obtained for the primary spectral parameters and the effective exchange interaction I. The quantity d In I/d In V = - 0.7 + 0.2 differs substantially from the theoretical data for palladium, which suggests a weaker volumetric dependence of I.
BibTeX: @article{panfilov1989iii, author = {Panfilov, A. S. and Pushkar, Y. Y. and Svechkarev, I. V.}, title = {Effect of pressure on exchange-enhanced zone paramagnetism of palladium alloys}, journal = {ZHURNAL EKSPERIMENTALNOI I TEORETICHESKOI FIZIKI}, publisher = {MEZHDUNARODNAYA KNIGA}, year = {1989}, volume = {95}, number = {2}, pages = {751-759}, note = {Sov. Phys. JETP, Vol. 68, Number 2, pp. 426-431}, url = {http://www.jetp.ac.ru/cgi-bin/dn/e_068_02_0426.pdf} }
Kabanov A.E., Burma N.G., Deineka E.Y., Fil' V.D.	'Non-collision' magnetoacoustic resonance in gallium [Abstract] [BibTeX]	1989	Fizika Nizkikh Temperatur Vol. 15(7), pp. 745-749	URL
Abstract: The predicted ≪non-collision≫ magnetoacoustic resonance (MAR) occuring under the condition of weak aperiodicity of the electron movement along quasi-open trajectories is experimentally detected and investigated. For the cross-section of the open region of the Fermi surface (FS) of gallium providing the extreme electron drift, the value of (∂3S/∂pξ3)pξextreme (S is the area of the corresponding section, pξ the Fermi momentum perpendicular to the vector of openness) is measured.
BibTeX: @article{Kabanov1989745, author = {Kabanov, A. E. and Burma, N. G. and Deineka, E. Yu. and Fil', V. D.}, title = {'Non-collision' magnetoacoustic resonance in gallium}, journal = {Fizika Nizkikh Temperatur}, year = {1989}, volume = {15}, number = {7}, pages = {745-749}, note = {cited By 0}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0024706245&partnerID=40&md5=e29baf1d20a8db0e3f1841c6e4a4e2b9} }
Desnenko V.A.	Nature of the magnetoplastic effect [Abstract] [BibTeX]	1989	Physics of Metals and Metallography Vol. 67(2), pp. 171-173	URL
Abstract: The flow stress of a ferromagnetic, nickel, for example, falls by Δσ in a pulsating magnetic field. This is called the magnetoplastic effect (MPE). In order to clarify the nature of the MPE, the values of Δσ and the fall in flow stress of polycrystalline nickel (99.95%) were determined in a pulsating magnetic field of strength H0=48 kA/m and frequency f=50 Hz at T=300, 77 and 4.2 K. The nature of the MPE consists in intensification of heat activated dislocation processes in a magnetized ferromagnetic owing not only to the effective stresses near stopped dislocations increased by domain walls, as previously suggested, but also generation of the heat of hysteresis during Barkhausen discontinuities and the appearance of Joule heat of eddy currents by the walls.
BibTeX: @article{Desnenko1989171, author = {Desnenko, V. A.}, title = {Nature of the magnetoplastic effect}, journal = {Physics of Metals and Metallography}, year = {1989}, volume = {67}, number = {2}, pages = {171-173}, note = {cited By 0}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0024889788&partnerID=40&md5=fcbe4111632f1882b1a1dcb733a53fc6} }
Savchenko N.V., Grechnev G.E.	Anisotropy of conduction electron g-factors in molybdenum and tungsten [Abstract] [BibTeX]	1989	Fizika Nizkikh Temperatur Vol. 15(6), pp. 656-659	URL
Abstract: The theoretical investigation of conduction electron g-factors in bcc transition metals molybdenum and tungsten is carried out. A pronounced anisotropy is found both for different extremal orbits on a given sheet and for different sheets of the Fermi surface in these metals.
BibTeX: @article{savchenko1989, author = {Savchenko, N. V. and Grechnev, G. E.}, title = {Anisotropy of conduction electron g-factors in molybdenum and tungsten}, journal = {Fizika Nizkikh Temperatur}, year = {1989}, volume = {15}, number = {6}, pages = {656-659}, url = {http://fnte.ilt.kharkov.ua/fnt/pdf/15/15-6/f15-0656r.pdf} }
Vertii A., Zvyagina G., Ivanchenko I., Popenko N., Tarapov S., Shestopalov V.	Resonance cells for millimeter-band spectrometer operating at T < 1°K [Abstract] [BibTeX]	1988	Instruments and experimental techniques New York Vol. 31(2 pt 1), pp. 381-385	URL
Abstract: Resonance cells for an EPR spectrometer operating at a range of 4.2-0.3°K in the millimeter band are described. It is shown that a cell in the form of an open resonator with an element with total internal reflection introduces the smallest heat losses into the evaporation chamber. EPR spectra are presented for Na HMBA CrV, in which line splitting is observed at temperatures of <0.9°K.
BibTeX: @article{Vertii1988381, author = {Vertii, A.A. and Zvyagina, G.A. and Ivanchenko, I.V. and Popenko, N.A. and Tarapov, S.I. and Shestopalov, V.P.}, title = {Resonance cells for millimeter-band spectrometer operating at T < 1°K}, journal = {Instruments and experimental techniques New York}, year = {1988}, volume = {31}, number = {2 pt 1}, pages = {381-385}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0024070688&partnerID=40&md5=9496beea30561f7ba991cf274c80cf7d} }
Vertii A., Zvyagina G., Popenko N.	Quasioptical open resonator with dielectric filling [BibTeX]	1988	Radiophysics and Quantum Electronics Vol. 31(5), pp. 434-441	DOI
BibTeX: @article{Vertii1988434, author = {Vertii, A.A. and Zvyagina, G.A. and Popenko, N.A.}, title = {Quasioptical open resonator with dielectric filling}, journal = {Radiophysics and Quantum Electronics}, publisher = {Kluwer Academic Publishers-Plenum Publishers}, year = {1988}, volume = {31}, number = {5}, pages = {434-441}, doi = {http://dx.doi.org/10.1007/BF01043607} }
Panfilov A.S., Pushkar Y.Y., Svechkarev I.V.	Temperature dependence of magnetovolume effect in vanadium and palladium [Abstract] [BibTeX]	1988	Fizika Nizkikh Temperatur Vol. 14(5), pp. 532-536	URL
Abstract: Using the levitation method, the dependence of magnetic susceptibility on pressure up to 2 kbar in vanadium, palladium and Pd0,95Rh0,05 alloy is studied at the temperatures 20.4 and 78 K. The results obtained and supplemented with data derived by other methods show a strong temperature dependence of the magnetovolume effect in palladium and the alloy and its invariance in vanadium. The low temperature data for pure metals are compared with theoretical calculation, which shows an appreciable discrepancy whose origin is not clear.
BibTeX: @article{panfilov1988, author = {Panfilov, A. S. and Pushkar, Y. Y. and Svechkarev, I. V.}, title = {Temperature dependence of magnetovolume effect in vanadium and palladium}, journal = {Fizika Nizkikh Temperatur}, publisher = {FIZIKA NIZKIKH TEMPERATUR}, year = {1988}, volume = {14}, number = {5}, pages = {532-536}, url = {http://fnt.ilt.kharkov.ua/fnt/pdf/14/14-5/f14-0532r.pdf} }
Mihalik M., Zentko A., Panfilov A., Svechkarev I.	Effect of pressure on the Curie temperature of annealed Fe-Ni-Cr-Mo-Si-B amorphous alloys [Abstract] [BibTeX]	1987	Czechoslovak Journal of Physics Vol. 37(1), pp. 16-18	DOI
Abstract: Effect of high pressure on the Curie temperature of annealed Fe30Ni36Cr12Mo2Si5B15 amorphous alloys has been investigated. It has been shown that the annealed samples e〉 hibit a smaller pressure dependence of Tc than "as-quenched" one.
BibTeX: @article{Mihalik198716, author = {Mihalik, M. and Zentko, A. and Panfilov, A.S. and Svechkarev, I.V.}, title = {Effect of pressure on the Curie temperature of annealed Fe-Ni-Cr-Mo-Si-B amorphous alloys}, journal = {Czechoslovak Journal of Physics}, publisher = {Kluwer Academic Publishers}, year = {1987}, volume = {37}, number = {1}, pages = {16-18}, doi = {http://dx.doi.org/10.1007/BF01597872} }
Gaiduk A.L., Zherlitsyn S.V., Panfilov A.S., Puzikov V.M., Stepanenko A.M., Fil V.D., Cherny A.S.	Anomalous behavior of elastic moduli in La1.8Sr0.2CuO4 ceramics [BibTeX]	1987	Fizika Nizkikh Temperatur Vol. 13(6), pp. 653-654	URL
BibTeX: @article{gaiduk1987, author = {Gaiduk, A. L. and Zherlitsyn, S. V. and Panfilov, A. S. and Puzikov, V. M. and Stepanenko, A. M. and Fil, V. D. and Cherny, A. S.}, title = {Anomalous behavior of elastic moduli in La1.8Sr0.2CuO4 ceramics}, journal = {Fizika Nizkikh Temperatur}, publisher = {FIZIKA NIZKIKH TEMPERATUR}, year = {1987}, volume = {13}, number = {6}, pages = {653-654}, url = {https://inis.iaea.org/search/searchsinglerecord.aspx?recordsFor=SingleRecord&RN=19012266} }
Verkin B.I., Banduryan B.B., Barylnik A.S., Batrak A.G., Bobrov N.L., Braude I.S., Galchinetskaya Y.L., Gaiduk A.L., Gurevich A.M., Demirskii V.V., Dotsenko V.I., Eropkin V.I., Zherlitsyn S.V., Isakina A.P., Kislyak I.F., Konovodchenko V.A., Lavrentev F.F., Litinskaya L.S., Mikheev V.A., Momot G.I., Natsik V.D., Nechiporenko I.N., Panfilov A.S., Pokhil Y.A., Prokhvatilov A.I., Rudavskii E.Y., Rybalchenko L.F., Svechkarev I.V., Stepanenko A.M., Strzhemechny M.A., Fedorchenko L.I., Fil V.D., Fisun V.V., Khomenko V.G., Chagovets V.K., Sheshin G.A., Yanson I.K.	Structure and physical properties of superconducting compounds Y(La)-Ba(Sr)-Cu-O [Abstract] [BibTeX]	1987	Fizika Nizkikh Temperatur Vol. 13(7), pp. 771-783	URL
Abstract: The structure and physical properties of superconducting compounds Y(La)-Ba(Sr)-Cu-O are studied, the compounds being prepared by the method of cryogenic dispersion of a charge consisting of premix oxides and carbonates. Electrical conductivity and critical current density of the superconductors are measured over a wide temperature range of 10~mK to 300~K. Degradation of the superconductor critical parameters in time and structural characteristics, magnetic susceptibility, heat capacity and acoustic properties are studied, and current-voltage characteristics are determined.
BibTeX: @article{verkin1987, author = {Verkin, B. I. and Banduryan, B. B. and Barylnik, A. S. and Batrak, A. G. and Bobrov, N. L. and Braude, I. S. and Galchinetskaya, Y. L. and Gaiduk, A. L. and Gurevich, A. M. and Demirskii, V. V. and Dotsenko, V. I. and Eropkin, V. I. and Zherlitsyn, S. V. and Isakina, A. P. and Kislyak, I. F. and Konovodchenko, V. A. and Lavrentev, F. F. and Litinskaya, L. S. and Mikheev, V. A. and Momot, G. I. and Natsik, V. D. and Nechiporenko, I. N. and Panfilov, A. S. and Pokhil, Y. A. and Prokhvatilov, A. I. and Rudavskii, E. Y. and Rybalchenko, L. F. and Svechkarev, I. V. and Stepanenko, A. M. and Strzhemechny, M. A. and Fedorchenko, L. I. and Fil, V. D. and Fisun, V. V. and Khomenko, V. G. and Chagovets, V. K. and Sheshin, G. A. and Yanson, I. K.}, title = {Structure and physical properties of superconducting compounds Y(La)-Ba(Sr)-Cu-O}, journal = {Fizika Nizkikh Temperatur}, publisher = {FIZIKA NIZKIKH TEMPERATUR}, year = {1987}, volume = {13}, number = {7}, pages = {771-783}, url = {https://arxiv.org/abs/1703.08707} }
Verkin B.I., Dmitriev V.M., Zvyagin A.I., Kosmyna M.B., Kutko V.I., Litinskaya L.S., Panfilov A.S., Pluzhnikov V.B., Prikhodko O.P., Saliichuk E.K., Seminozhenko V.P., Svechkarev I.V., Svetlov V.N., Solovev A.L., Khristenko E.V., Churilov G.E.	Electrical and magnetic properties of superconducting compounds La(Ba,Sr)CuO and YBaCuO [Abstract] [BibTeX]	1987	Fizika Nizkikh Temperatur Vol. 13(8), pp. 853-857	URL
Abstract: Specific features of electrical resistivity and magnetic properties of high-resistance metaloxide ceramics based on lanthanum and yttrium are considered. The data indicate that superconductivity for the above systems is realized through a network of conducting channels. The superconducting gap width is estimated to be 2delta ~(5.2-5.9)*kTc, and its temperature dependence, as well as Hc1, values for some ceramics, are found.
BibTeX: @article{verkin1987ii, author = {Verkin, B. I. and Dmitriev, V. M. and Zvyagin, A. I. and Kosmyna, M. B. and Kutko, V. I. and Litinskaya, L. S. and Panfilov, A. S. and Pluzhnikov, V. B. and Prikhodko, O. P. and Saliichuk, E. K. and Seminozhenko, V. P. and Svechkarev, I. V. and Svetlov, V. N. and Solovev, A. L. and Khristenko, E. V. and Churilov, G. E.}, title = {Electrical and magnetic properties of superconducting compounds La(Ba,Sr)CuO and YBaCuO}, journal = {Fizika Nizkikh Temperatur}, publisher = {FIZIKA NIZKIKH TEMPERATUR}, year = {1987}, volume = {13}, number = {8}, pages = {853-857}, url = {https://inis.iaea.org/search/search.aspx?orig_q=RN:19071887} }
Skriver H.L., Grechnev G.E., Kruglov V.O., Svechkarev I.V.	Electronic structure of FeGe2 [Abstract] [BibTeX]	1987	Fizika Nizkikh Temperatur Vol. 13(7), pp. 765-768	URL
Abstract: A theoretical investigation of the electronic structure of FeGe2 has been carried out in the framework of the LMTO method. The presence of a sharp peak in the electronic density of states at the Fermi level and the pronounced p-d hybridization in the conduction band are revealed. It is found that there is a strong exchange enhancement of the spin paramagnetism in FeGe2. The peculiarities of the de Haas-van Alphen effect in FeGe2 are explained qualitatively.
BibTeX: @article{skriverh1987, author = {Skriver, H. L. and Grechnev, G. E. and Kruglov, V. O. and Svechkarev, I. V.}, title = {Electronic structure of FeGe2}, journal = {Fizika Nizkikh Temperatur}, year = {1987}, volume = {13}, number = {7}, pages = {765-768}, url = {http://fnte.ilt.kharkov.ua/fnt/pdf/13/13-7/f13-0765r.pdf} }
Grechnev G., Savchenko N., Svechkarev I., Antonov V., Zhalko-Titarenko A., Lee M., Perz J.	Anisotropy of conduction electrons zeeman splitting in palladium and gold [Abstract] [BibTeX]	1987	Fizika Nizkikh Temperatur Vol. 13(11), pp. 1219-1222	URL
Abstract: The theoretical investigation of conduction electron g-factors in palladium and gold is carried out. It is established that g-factors deviate considerably from the free-electron value for some Fermi surface sheets of these metals. A pronounced anisotropy is found for the extremal orbits on the GAMMA //6 sheet and X-pockets in palladium. The results are in general agreement with data from DHVA and CESR experiments.
BibTeX: @article{Grechnev19871219, author = {Grechnev, G.E. and Savchenko, N.V. and Svechkarev, I.V. and Antonov, V.N. and Zhalko-Titarenko, A.V. and Lee, M.J.G. and Perz, J.M.}, title = {Anisotropy of conduction electrons zeeman splitting in palladium and gold}, journal = {Fizika Nizkikh Temperatur}, year = {1987}, volume = {13}, number = {11}, pages = {1219-1222}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0023456032&partnerID=40&md5=a38d6b8f5c223bd508aceda2c1128421} }
Grechnev G.E., Svechkarev I.V.	Electronic structure and magnetic properties of intermatallic compound TiCo [Abstract] [BibTeX]	1987	Fizika Nizkikh Temperatur Vol. 13(5), pp. 547-551	URL
Abstract: The theoretical investigation of the electronic structure and thermodynamical properties of the compound TiCo is carried out at low temperatures. The origin of the compound stability is established. It is proved that the high exchange enhancement of spin susceptibility takes place in TiCo. The coexistance of strong paramagnetism and the superconductivity in TiCo is explained. The parameters of electron-phonon and electron-paramagnon interactions are determined.
BibTeX: @article{grechnev1987-p547, author = {Grechnev, G. E. and Svechkarev, I. V.}, title = {Electronic structure and magnetic properties of intermatallic compound TiCo}, journal = {Fizika Nizkikh Temperatur}, year = {1987}, volume = {13}, number = {5}, pages = {547-551}, url = {http://fnte.ilt.kharkov.ua/fnt/pdf/13/13-5/f13-0547r.pdf} }
Grechnev G., Svechkarev I., Ushakova N.	Influence of temperature on the electronic energy spectrum of aluminium [Abstract] [BibTeX]	1986	Physics of Metals and Metallography Vol. 62(1), pp. 186-189	URL
Abstract: In previous work the electronic energy spectra (EES) of certain metals at finite temperatures were calculated on the basis of empirical pseudopotentials and experimental results on the mean-square thermal atomic displacements. The question arose of the scale of the temperature effects in the EES of metals with cubic lattices where there is no change in anisotropy during thermal expansion and the fall in electron density becomes an important factor. In this study the authors made a theoretical investigation of the EES of aluminium in the range of existence of the solid phase (0 K less than T less than 900 K).
BibTeX: @article{Grechnev1986186, author = {Grechnev, G.Ye. and Svechkarev, I.V. and Ushakova, N.V.}, title = {Influence of temperature on the electronic energy spectrum of aluminium}, journal = {Physics of Metals and Metallography}, year = {1986}, volume = {62}, number = {1}, pages = {186-189}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0022938298&partnerID=40&md5=0aeefa3db219a81d456bf37fd3aecb91} }
Klimker H., Perz J., Svechkarev I., Dolgopolov D.	Low temperature magnetostriction in FeSi [Abstract] [BibTeX]	1986	Journal of Magnetism and Magnetic Materials Vol. 62(2-3), pp. 339-345	DOI
Abstract: The longitudinal and transverse components of magnetostriction of the cubic B-20 type compound FeSi have been measured in the temperature range 1 to 29 K. The transverse magnetostriction is found to be positive and highly anisotropic; the longitudinal magnetostriction is negative and much smaller. The low temperature volume derivative of susceptibility.
BibTeX: @article{Klimker1986339, author = {Klimker, H. and Perz, J.M. and Svechkarev, I.V. and Dolgopolov, D.G.}, title = {Low temperature magnetostriction in FeSi}, journal = {Journal of Magnetism and Magnetic Materials}, year = {1986}, volume = {62}, number = {2-3}, pages = {339-345}, doi = {http://dx.doi.org/10.1016/0304-8853(86)90163-0} }
Grechnev G., Svechkarev I.	Magnetic susceptibility of Be//1//0//0// minus //xCu//x alloys [Abstract] [BibTeX]	1985	Physics of Metals and Metallography Vol. 60(4), pp. 89-95	URL
Abstract: An experimental and theoretical investigation was made of the susceptibility of single crystals of pure beryllium and alloys Be//1// minus //xCu//x (with x equals 0. 54 and x equals 1. 34) in the temperature range 77 to 1500 K. Diamagnetism falls with rise in temperature. The change of the diamagnetic extremum in beryllium-copper alloys was also studied. On the basis of a calculation of the band structure of Be and data on the electronic spectrum of Be(Cu) the authors obtain a quantitative description of the temperature dependences of susceptibility components in the framework of the proposed theory of magnetism of beryllium.
BibTeX: @article{Grechnev198589, author = {Grechnev, G.Ye. and Svechkarev, I.V.}, title = {Magnetic susceptibility of Be//1//0//0// minus //xCu//x alloys}, journal = {Physics of Metals and Metallography}, year = {1985}, volume = {60}, number = {4}, pages = {89-95}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0022302161&partnerID=40&md5=e3c4aa7df031388b976ce94ba2b01237} }
Panfilov A.S.	Influence of pressure on the electrical-properties of iron monosilicide [BibTeX]	1985	SOVIET PHYSICS SEMICONDUCTORS-USSR Vol. 19(10), pp. 1159-1160
BibTeX: @article{panfilov1985, author = {Panfilov, A. S.}, title = {Influence of pressure on the electrical-properties of iron monosilicide}, journal = {SOVIET PHYSICS SEMICONDUCTORS-USSR}, publisher = {AMER INST PHYSICS}, year = {1985}, volume = {19}, number = {10}, pages = {1159-1160} }
Grechnev G.E.	Effect of high intensity ultrasound on band structure of metals [Abstract] [BibTeX]	1985	Fizika Nizkikh Temperatur Vol. 11(1), pp. 102-106	URL
Abstract: The band structure of the nontransition metal electron spectrum is calculated by the pseudopotential method in the presence of a standing ultrasonic wave. It is found that near the Brillouin zone faces the superstructural splittings in the spectrum induced by an additional long period are governed by the Umklapp-time electron transitions and significantly exceed "sonic" gaps near the conduction zone bottom. The main energy gaps on the Bragg planes corresponding to the reciprocal lattice vectors G, which are quasi-collinear with respect to the sound amplitude u0, decrease essentially as u0 increases.
BibTeX: @article{grechnev1985, author = {Grechnev, G. E.}, title = {Effect of high intensity ultrasound on band structure of metals}, journal = {Fizika Nizkikh Temperatur}, year = {1985}, volume = {11}, number = {1}, pages = {102-106}, url = {http://fnte.ilt.kharkov.ua/fnt/pdf/11/11-1/f11-0102r.pdf} }
Franus-Muir E., Fawcett E., Pluzhnikov V.	Magnetostriction of antiferromagnetic FeGe2 [Abstract] [BibTeX]	1984	Solid State Communications Vol. 52(6), pp. 615-617	DOI
Abstract: The anisotropic magnetostriction of FeGe2 is measured for magnetic field along the [1 0 0] and [1 1 0] axes at temperature 4.2 K and along [1 0 0] from 77 to 300 K. The behaviour is consistent with spin reorientation in the basal plane. The saturation magnetostriction and the characteristic field required to produce saturation decrease with increasing temperature and approach zero at the lower transition temperature, TK reversed tilde equals 265 K. This suggests that the spins flip from the basal plane into the direction of the tetragonal [0 0 1] axis at TK.
BibTeX: @article{Franus-Muir1984615, author = {Franus-Muir, E. and Fawcett, E. and Pluzhnikov, V.}, title = {Magnetostriction of antiferromagnetic FeGe2}, journal = {Solid State Communications}, year = {1984}, volume = {52}, number = {6}, pages = {615-617}, doi = {http://dx.doi.org/10.1016/0038-1098(84)90890-1} }
Grechnev G., Svechkarev I.	Influence of temperature on the band structure of cadmium and beryllium [Abstract] [BibTeX]	1984	Physics of Metals and Metallography Vol. 57(2), pp. 23-29	URL
Abstract: Semi-empirical non-local pseudopotentials and experimental information on the character of crystal lattice oscillations are used in a theoretical investigation of the electronic spectra in a wide temperature range. A number of peculiarities in the electronic spectra are predicted and the temperature dependences of susceptibility explained on the basis of calculations of the band structure. Allowance for the Debye-Waller factor in the framework of the pseudopotential method gives a reliable quantitative description of thermal rearrangement of the band structure.
BibTeX: @article{Grechnev198423, author = {Grechnev, G.Ye. and Svechkarev, I.V.}, title = {Influence of temperature on the band structure of cadmium and beryllium}, journal = {Physics of Metals and Metallography}, year = {1984}, volume = {57}, number = {2}, pages = {23-29}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0021727461&partnerID=40&md5=14aebab084608183159f52cc4ae22eef} }
Grechnev G., Svechkarev I., Khotkevich V.	Band structure and stability of the compound Cd//3Mg [Abstract] [BibTeX]	1984	Soviet Journal of Low Temperature Physics (English Translation of Fizika Nizkikh Temperatur) Vol. 10(5), pp. 287-289	URL
Abstract: Using nonlocal semi-empirical pseudopotentials, we calculate the electron energy spectrum of the compound Cd//3Mg at T equals 0. The detailed dependences of the density of electron states indicate significant differences between the band structures of Cd//3Mg and pure cadmium. We trace the evolution of the total energy of the crystal during the transition from cadmium to the disorder phase and then the ordered phase of Cd//3Mg. The energy of the band structure is shown to be a minimum in the order phase.
BibTeX: @article{Grechnev1984287, author = {Grechnev, G.E. and Svechkarev, I.V. and Khotkevich, V.V.}, title = {Band structure and stability of the compound Cd//3Mg}, journal = {Soviet Journal of Low Temperature Physics (English Translation of Fizika Nizkikh Temperatur)}, year = {1984}, volume = {10}, number = {5}, pages = {287-289}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0021423892&partnerID=40&md5=a7466e2464d244c601bd128283796116} }
Gudkov V., Fil V.	Ultrasonic Wave Field Transport by Conduction Electrons in Indium [Abstract] [BibTeX]	1984	physica status solidi (b) Vol. 121(1), pp. 433-440	DOI
Abstract: The phenomenon of electronic transport of ultrasonic fields corresponding to a circularly polarized wave is observed and studied in a single crystal of superpure indium under propagation of transverse ultrasonic radio‐wave pulses along tetragonal crystallographic axis under Doppler‐shifted acoustic cyclotron resonance conditions in a longitudinal magnetic field. The most effective transport is proved to be in the range of sufficient deformation interaction of conduction electrons with the ultrasonic wave. A Gaussian curvature of the resonant band of electrons is determined.
BibTeX: @article{Gudkov1984433, author = {Gudkov, V.V. and Fil, V.D.}, title = {Ultrasonic Wave Field Transport by Conduction Electrons in Indium}, journal = {physica status solidi (b)}, year = {1984}, volume = {121}, number = {1}, pages = {433-440}, doi = {http://dx.doi.org/10.1002/pssb.2221210147} }
Pluzhnikov V., Maszkiewicz M., Fawcett E.	Magnetostriction of dilute hydrogenated palladium-rhodium alloys [Abstract] [BibTeX]	1984	Journal of Physics F: Metal Physics Vol. 14(10), pp. 2411-2418	DOI
Abstract: The longitudinal and transverse magnetostriction of polycrystalline Pd, Pd99Rh1, Pd97Rh3 and Pd 95Rh5 is measured at 4.2K before and after charging with about 1 at.% H. The alloys are believed to be in the alpha phase and the systematic decrease in the volume magnetostriction is explained in a semi-rigid band model as being due to filling the 4d band at a rate of 0.3+or-0.2 states per H atom. The shape magnetostriction is unchanged by hydrogenation.
BibTeX: @article{Pluzhnikov19842411, author = {Pluzhnikov, V. and Maszkiewicz, M. and Fawcett, E.}, title = {Magnetostriction of dilute hydrogenated palladium-rhodium alloys}, journal = {Journal of Physics F: Metal Physics}, year = {1984}, volume = {14}, number = {10}, pages = {2411-2418}, doi = {http://dx.doi.org/10.1088/0305-4608/14/10/019} }
Pecherskaya V.I., Bolshutkin D.N., Desnenko V.A., Ilichev V.Y., Yushchenko K.A.	Peculiarities of the low-temperature electrical and magnetic properties in Fe-Cr-Ni-Mn alloys. [Abstract] [BibTeX]	1984	Advances in Cryogenic Engineering Vol. 30, pp. 483-487	DOI
Abstract: The aim of this work was to investigate electrical and magnetic properties of Fe-Cr-Ni-Mn alloys in the temperature range 4. 2 to 293 K. To investigate the electrical resistivity and magnetic susceptibility, chi , of Fe-18Cr-(6-16)Ni-4Mn alloys, samples 30 mm in length and 2 mm in diameter were used. Electrical resistance, R, was measured with the compensation potentiometric technique.
BibTeX: @conference{Pecherskaya1984483, author = {Pecherskaya, V. I. and Bolshutkin, D. N. and Desnenko, V. A. and Ilichev, V. Ya. and Yushchenko, K. A.}, title = {Peculiarities of the low-temperature electrical and magnetic properties in Fe-Cr-Ni-Mn alloys.}, journal = {Advances in Cryogenic Engineering}, publisher = {Plenum Press, New York, NY, USA}, year = {1984}, volume = {30}, pages = {483-487}, note = {cited By 0}, doi = {http://dx.doi.org/10.1007/978-1-4613-9868-4_56} }
Pecherskaya V.I., Bolshutkin D.N., Desnenko V.A., Ilichev V.Y.	Electrical and magnetic properties of the Fe18Cr(30–40)Ni alloys at low temperatures [Abstract] [BibTeX]	1984	Physica Status Solidi (a) Vol. 81(2), pp. 507-512	DOI
Abstract: The electrical and magnetic properties of Fe18Cr(30–40)Ni alloys with a double magnetic transition “paramagnetic‐ferromagnetic‐spin glass” are investigated at low temperatures. New experimental results concerning these magnetic traneformations are obtained. Changes in the properties considerably differing from the ones usually observed in homogenous magnetics at Curie temperature are found for the high‐temperature transition “paramagnetic‐ferromagnetic”. Data indicating the destruction of the infinite ferromagnetic cluster at the low temperature transition “ferromagnetic‐spin glass” are obtained. The finite ferromagnetic clusters forming at high temperatures play an important role in both the magnetic transitions.
BibTeX: @article{Pecherskaya1984507, author = {Pecherskaya, V. I. and Bolshutkin, D. N. and Desnenko, V. A. and Ilichev, V. Ya.}, title = {Electrical and magnetic properties of the Fe18Cr(30–40)Ni alloys at low temperatures}, journal = {Physica Status Solidi (a)}, year = {1984}, volume = {81}, number = {2}, pages = {507-512}, note = {cited By 1}, doi = {http://dx.doi.org/10.1002/pssa.2210810212} }
Khotkevich V.V., Pluzhnikov V.B., Svechkarev I.V., Grechnev G.E., Anderson D.R., Pikett U.	Electron energy spectrum and De Haas-Van Alphen effect in Cd3Mg ordered compound [Abstract] [BibTeX]	1984	Fizika Nizkikh Temperatur Vol. 10(4), pp. 431-434	URL
Abstract: De Haas-van Alphen oscillations are observed in the ordered intermetallic compound Cd3Mg at 1.5 to 4.2 K in the field up to 70 kG. The angular dependence of frequency oscillations in the range of 2.1 to 6.0 MG is studied. Effective masses of carriers and the Dingle temperature are measUred for some characteristic orientations of the magnetic field With respect to the crystal axes. The band structure of Cd3Mg is calculated on the basis of the model Animalu-Heine pseudopotentials. The model Fermi surface of Cd3Mg, is constructed and the interpretation of the oscillations observed experimentally is proposed.
BibTeX: @article{khotkevich1984, author = {Khotkevich, V. V. and Pluzhnikov, V. B. and Svechkarev, I. V. and Grechnev, G. E. and Anderson, D. R. and Pikett, U.}, title = {Electron energy spectrum and De Haas-Van Alphen effect in Cd3Mg ordered compound}, journal = {Fizika Nizkikh Temperatur}, year = {1984}, volume = {10}, number = {4}, pages = {431-434}, url = {https://inis.iaea.org/search/searchsinglerecord.aspx?recordsFor=SingleRecord&RN=16035775} }
Fawcett E., Pluzhnikov V.	Paramagnetostriction of transition metals [Abstract] [BibTeX]	1983	Physica B+C Vol. 119(1-2), pp. 161-166	DOI
Abstract: Measurements of the magnetostriction of cubic paramagnetic transition metals are reviewed and new data for the hexagonal metals Zr, Ti and Sc are presented. In Pd and PdRh alloys the large volume magnetostriction is associated with the exchange-enhanced spin susceptibility, while the explanation for the relatively large shape magnetostriction is still in question. In Mo and W the anisotropy of the magnetostriction is attributed to the orbital susceptibility, but in that case the shape magnetostriction for V and Sc is surprisingly small.
BibTeX: @article{Fawcett1983161, author = {Fawcett, E. and Pluzhnikov, V.}, title = {Paramagnetostriction of transition metals}, journal = {Physica B+C}, year = {1983}, volume = {119}, number = {1-2}, pages = {161-166}, doi = {http://dx.doi.org/10.1016/0378-4363(83)90183-3} }
Desnenko V.A.	On changes in nickel yield stress at low temperature and magnetic field variations [Abstract] [BibTeX]	1983	Fizika Metallov I Metallovedenie Vol. 55(6), pp. 1187-1193	URL
Abstract: The analysis of characteristic changes of nickel yield stress caused by imposition and removing stationary magnetic field H=420 Oe at 300, 77, 4.2 K and magnetic field H <34 kOe at 4.2 K is conducted. It is concluded that most essential reasons for observed changes of the s-n diagram under the action of magnetic fields in certain conditions are the following: fault of nickel elasticity modulus, Joule heating of a sample by eddy currents and a phenomenon of pulling inside solenoid of a part of the sample occuring in an inhomogeneous magnetic field.
BibTeX: @article{desnenko1983, author = {Desnenko, V. A.}, title = {On changes in nickel yield stress at low temperature and magnetic field variations}, journal = {Fizika Metallov I Metallovedenie}, publisher = {GOSUDARSTVENNOE NAUCHNO-TEKH}, year = {1983}, volume = {55}, number = {6}, pages = {1187-1193}, url = {https://inis.iaea.org/search/search.aspx?orig_q=RN:15012709} }
Pecherskaya V.I., Bolshutkin D.N., Desnenko V.A., Ilichev V.Y.	Electrical and magnetic properties of rapidly and slowly cooled 18Cr(10-25)Ni alloys at low temperatures [Abstract] [BibTeX]	1983	Cryogenics Vol. 23(11), pp. 608-610	DOI
Abstract: Electrical and magnetic properties of the 18Cr(10-25)Ni alloys cooled rapidly and slowly from 1100°C have been studied in the low temperature range. The results show that slow cooling leads to a more favourable situation for the cluster structure formation than rapid cooling.
BibTeX: @article{Pecherskaya1983608, author = {Pecherskaya, V. I. and Bolshutkin, D. N. and Desnenko, V. A. and Ilichev, V. Ya.}, title = {Electrical and magnetic properties of rapidly and slowly cooled 18Cr(10-25)Ni alloys at low temperatures}, journal = {Cryogenics}, year = {1983}, volume = {23}, number = {11}, pages = {608-610}, note = {cited By 0}, doi = {http://dx.doi.org/10.1016/0011-2275(83)90035-8} }
Grechnev G.E.	Effect of pressure and impurities on the electronic spectum of cadmium [Abstract] [BibTeX]	1983	Fizika Nizkikh Temperatur Vol. 9(10), pp. 1060-1067	URL
Abstract: Using semiempirical nonlocal pseudopotentials, calculation is made of cadmium electronic spectrum changes at helium temperatures under uniform and uniaxial compression, as well as when doping with isovalent impurities (magnesium and mercury). Local dampingpara meters are calculated for electronic states in Cd--(Mg) and Cd--(Hg). A number of electronic topological transitions are predicted at K and L symmetry points, and on Sigma symmetry line in the Brillouin zone. The relation between specific behavior of some physical characteristics of Cd--Mg and Cd--Hg alloys, as well as of pure Cd under pressure, and topological changes of the Fermi surface is discussed.
BibTeX: @article{grechnev1983, author = {Grechnev, G. E.}, title = {Effect of pressure and impurities on the electronic spectum of cadmium}, journal = {Fizika Nizkikh Temperatur}, year = {1983}, volume = {9}, number = {10}, pages = {1060-1067}, url = {http://fnte.ilt.kharkov.ua/fnt/pdf/9/9-10/f09-1060r.pdf} }
Vorontsov S.A., Grechnev G.E.	Temperature dependence of Knight shift in Cd-Mg alloys [Abstract] [BibTeX]	1983	Fizika Nizkikh Temperatur Vol. 9(8), pp. 884-887	URL
Abstract: The contribution to the isotropic part of the Knight shift in cadmium from the states on the narrow neck of the hole surface of the second zone (monster) is calculated. Because of EF proximity to the point where the Fermi surface topology changes, the behaviour of Kiso with rising temperature and magnesium impurity addition is mainly governed by the electron spectrum rearrangement due to the effects of the Debye-Waller factor, the impurity potential and the lattice parameter variations. The calculated dependences of Kiso on temperature and concentration in Cd[100-x]Mg[x] alloys are consistent with experimental results.
BibTeX: @article{vorontsov1983, author = {Vorontsov, S. A. and Grechnev, G. E.}, title = {Temperature dependence of Knight shift in Cd-Mg alloys}, journal = {Fizika Nizkikh Temperatur}, year = {1983}, volume = {9}, number = {8}, pages = {884-887}, url = {https://inis.iaea.org/search/search.aspx?orig_q=RN:15044955} }
Fil V., Gaiduk A., Denisenko V.	Propagation of nonlinear acoustic waves in gallium [Abstract] [BibTeX]	1982	Journal of Low Temperature Physics Vol. 47(3-4), pp. 207-222	DOI
Abstract: We study nonlinear phenomena which occur during strong sound signal propagation in superpure Ga and are due to the perturbation of the electron subsystem in the metal. Although the observations are in qualitative agreement with theoretical concepts in a number of aspects, there are effects which still lack adequate theoretical interpretation, in particular, an oscillatory dependence of the harmonic amplitudes on magnetic field which is linear with respect to H1/2, and appreciable nonlinear distortions of the sound pulse envelope accompanied by the acoustic noise generation.
BibTeX: @article{Fil1982207, author = {Fil, V.D. and Gaiduk, A.L. and Denisenko, V.I.}, title = {Propagation of nonlinear acoustic waves in gallium}, journal = {Journal of Low Temperature Physics}, publisher = {Kluwer Academic Publishers-Plenum Publishers}, year = {1982}, volume = {47}, number = {3-4}, pages = {207-222}, doi = {http://dx.doi.org/10.1007/BF00683727} }
Pluzhnikov V., Fawcett E.	Paramagnetostriction of palladium and palladium-rhodium alloys [Abstract] [BibTeX]	1982	Journal of Physics F: Metal Physics Vol. 12(7), pp. 1467-1474	DOI
Abstract: The longitudinal and transverse magnetostriction of single-crystal Pd and three PdRh alloys was measured. The volume magnetostriction was found to increase as Rh was added to Pd up to a maximum value about a factor of four larger than that of Pd at about 5 at.% Rh in Pd. The shape magnetostriction remained constant and roughly equal to the large value observed in Pd. This strong anisotropy of the magnetostriction is therefore not due to the stress-dependent anisotropy of the exchange-enhanced spin susceptibility, and is more likely to result from the stress-independent anisotropy of the spin-orbit interaction.
BibTeX: @article{Pluzhnikov19821467, author = {Pluzhnikov, V. and Fawcett, E.}, title = {Paramagnetostriction of palladium and palladium-rhodium alloys}, journal = {Journal of Physics F: Metal Physics}, year = {1982}, volume = {12}, number = {7}, pages = {1467-1474}, doi = {http://dx.doi.org/10.1088/0305-4608/12/7/017} }
Pluzhnikov V., Feder D., Fawcett E.	Ultrasonic attenuation anomalies at the two transitions in antiferromagnetic FeGe2 [Abstract] [BibTeX]	1982	Journal of Magnetism and Magnetic Materials Vol. 27(3), pp. 343-346	DOI
Abstract: The attenuation of longitudinal and shear sound waves is measured through the Néel temperature, TN≈286 K, and the lower transition temperature, TK≈265 K, of FeGe2. Longitudinal sound with wavevector q along the [100] axis of this tetragonal antiferromagnetic metal shows an attenuation peak at TN, which is reversibly suppressed by compressive uniaxial stress σ along [010]. The estimated pressure dependence of TN is dTN/dp=(-2.8±0.3) mK bar-1. The peak at TN shows thermal and stress hysteresis, which suggests that it is associated with domain wall motion and that this transition is first order.
BibTeX: @article{Pluzhnikov1982343, author = {Pluzhnikov, V. and Feder, D. and Fawcett, E.}, title = {Ultrasonic attenuation anomalies at the two transitions in antiferromagnetic FeGe2}, journal = {Journal of Magnetism and Magnetic Materials}, year = {1982}, volume = {27}, number = {3}, pages = {343-346}, doi = {http://dx.doi.org/10.1016/0304-8853(82)90095-6} }
Fil' V., Gaiduk A., Denisenko V.	Nonsteady nonlinear acoustic effects in GA [Abstract] [BibTeX]	1981	Physica B+C Vol. 107(1-3), pp. 117-118	DOI
Abstract: Experimental data showing perhaps the development of turbulent processes in the electron subsystem in a metal by the propagation of the intensive sound signal are presented in this work.
BibTeX: @article{Fil'1981117, author = {Fil', V.D. and Gaiduk, A.L. and Denisenko, V.I.}, title = {Nonsteady nonlinear acoustic effects in GA}, journal = {Physica B+C}, year = {1981}, volume = {107}, number = {1-3}, pages = {117-118}, doi = {http://dx.doi.org/10.1016/0378-4363(81)90365-X} }
Bol'shutkin D.N., Desnenko V.A., Il'yichev V.Y., Pestryakov V.A.	Low-temperature plastic deformation and susceptibility of steels Kh18N(20-25) [Abstract] [BibTeX]	1981	Physics of Metals and Metallography Vol. 51(2), pp. 50-56	URL
Abstract: Changes of magnetic susceptibility of chi Kh18N(20-25) steels are studied at 4.2, 77 and 300 K, which are caused by elastic and plastic deformation. Magnetoelastic changes chi which appeared to be different at different temperatures, are explained by differences in steel magnetic state. A possibility arises to study thermal effects at low-temperature plastic deformation of shown materials due to extremal temperature dependence of magnetic susceptibility. The increase of sample temperature at ΔT approximately 0.2 K is shown in the process of plastic deformation at the rate of 0.5 mm/min at 4.2 K. At jump deformation at the moment of loading stall in the deformation zone temperature increases up to 125 K.
BibTeX: @article{Bol'shutkin198150, author = {Bol'shutkin, D. N. and Desnenko, V. A. and Il'yichev, V. Ya. and Pestryakov, V. A.}, title = {Low-temperature plastic deformation and susceptibility of steels Kh18N(20-25)}, journal = {Physics of Metals and Metallography}, year = {1981}, volume = {51}, number = {2}, pages = {50-56}, note = {cited By 0}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0019760739&partnerID=40&md5=e96fc0c1bb8d9d61011b6ee5ecf2ee8d} }
Bolshutkin D.N., Desnenko V.A.	Stress variation in normal metals with magnetic-field On and Off [Abstract] [BibTeX]	1981	Fizika Nizkikh Temperatur Vol. 7(5), pp. 652-657	URL
Abstract: Reported are results of a study of effects of experimental conditions on changes in load at the dynamometer under flow stress in aluminium at T = 4.2 K and in a dc magnetic field of 27 k0e. The analysis of experimental data indicates that the observed load changes are due to forces of electrodynamic and magnetostatic origin.
BibTeX: @article{bolshutkin1981, author = {Bolshutkin, D. N. and Desnenko, V. A.}, title = {Stress variation in normal metals with magnetic-field On and Off}, journal = {Fizika Nizkikh Temperatur}, publisher = {FIZIKA NIZKIKH TEMPERATUR}, year = {1981}, volume = {7}, number = {5}, pages = {652-657}, url = {https://fnte.ilt.kharkov.ua/result.php?Month=5&Subj=0&Year=0} }
Grechnev G.E., Svechkarev I.V.	Effect of isovalent impurities and pressure on the magnetic properties and energy spectrum parameters of cadmium [Abstract] [BibTeX]	1981	Fizika Nizkikh Temperatur Vol. 7(9), pp. 1137-1146	URL
Abstract: The previously developed theory of magnetism of simple hcp metals is employed to analyze magnetic susceptibility of pure cadmium crystals containing homovalent impurities under pressure at low (T=20 K) temperatures. The effect of impurity scattering on the magnetic susceptibility is taken into account in terms of an ''effective temperature'' determined from measutements. By comparing experimental and theoretical values of the magnetic susceptibility we have determined some of the energy-spectrum parameters of pure cadmium, as well as band splittings and the relative position of the Fermi level -as functions of the concentration of magnesium and mercury impurities and the pressure. Quantitative characteristics of the cadmium pseudopotential near the first form factor's zero is also determined in the ''on-Fermi-sphere'' approximation.
BibTeX: @article{grechnev1981, author = {Grechnev, G. E. and Svechkarev, I. V.}, title = {Effect of isovalent impurities and pressure on the magnetic properties and energy spectrum parameters of cadmium}, journal = {Fizika Nizkikh Temperatur}, year = {1981}, volume = {7}, number = {9}, pages = {1137-1146}, url = {https://inis.iaea.org/search/search.aspx?orig_q=RN:13704103} }
Perz J., Svechkarev I., Templeton I.	Hydrostatic pressure dependence of the fermi surface of rhenium [Abstract] [BibTeX]	1980	Canadian journal of physics Vol. 58(2), pp. 194-199	DOI
Abstract: The derivatives with respect to hydrostatic pressure of nine extremal cross-sectional areas of the Fermi surface of the hexagonal transition metal rhenium have been measured by the fluid helium de Haas van Alphen phase shift technique. With the field along left bracket 0001 right bracket , oscillations have been observed that correspond to a branch which appeared to vanish near this direction in previous de Haas van Alphen studies. Clear evidence has been observed of the degeneracy along the A-L line on the hexagonal face of the Brillouin zone.
BibTeX: @article{Perz1980194, author = {Perz, J.M. and Svechkarev, I.V. and Templeton, I.M.}, title = {Hydrostatic pressure dependence of the fermi surface of rhenium}, journal = {Canadian journal of physics}, year = {1980}, volume = {58}, number = {2}, pages = {194-199}, doi = {http://dx.doi.org/10.1139/p80-031} }
Svechkarev I., Fawcett E., Holroyd F.	Uniaxial stress-dependence of the Fermi surface of antiferromagnetic FeGe2 [Abstract] [BibTeX]	1980	Solid State Communications Vol. 35(3), pp. 297-299	DOI
Abstract: The oscillatory magnetostriction and torque of FeGe2 are measured to determine the uniaxial stress-dependence of the Fermi surface of this antiferromagnetic metal. A new low-frequency branch of the de Haas-van Alphen spectrum has a large and strongly anisotropic stress-dependence, while that of the high-frequency branch is fairly isotropic and consistent in sign and order of magnitude with previous pressure measurements.
BibTeX: @article{Svechkarev1980297, author = {Svechkarev, I.V. and Fawcett, E. and Holroyd, F.W.}, title = {Uniaxial stress-dependence of the Fermi surface of antiferromagnetic FeGe2}, journal = {Solid State Communications}, year = {1980}, volume = {35}, number = {3}, pages = {297-299}, doi = {http://dx.doi.org/10.1016/0038-1098(80)90501-3} }
Bol'shutkin D.N., Desnenko V.A., Il'yichev V.Y.	Low-temperature plastic deformation of steels Kh18N(10-15) [Abstract] [BibTeX]	1980	Physics of Metals and Metallography Vol. 50(4), pp. 131-136	URL
Abstract: The variation in susceptibility during elastic and plastic deformation at low temperatures is due to the formation of a ferromagnetic alpha phase as a result of the martensitic gamma yields alpha transformation, and to the magnetoelasticity of the alpha and gamma phases. The mean internal stresses in alpha phase crystallites are greater at lower temperatures and higher nickel concentrations. Spasmodic deformation at 4.2 K is not connected with the martensitic transformation.
BibTeX: @article{Bol'shutkin1980131, author = {Bol'shutkin, D. N. and Desnenko, V. A. and Il'yichev, V. Ya.}, title = {Low-temperature plastic deformation of steels Kh18N(10-15)}, journal = {Physics of Metals and Metallography}, year = {1980}, volume = {50}, number = {4}, pages = {131-136}, note = {cited By 1}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0019107921&partnerID=40&md5=bd635d881eea2180e6e96534480b5ba7} }
Bol'shutkin D.N., Desnenko V.A., Il'yichev V.Y.	Magnetic susceptibility of steels Kh18N(10-25) in the range 4.2-300 K [Abstract] [BibTeX]	1980	Physics of Metals and Metallography Vol. 49(2), pp. 50-55	URL
Abstract: The temperature dependence of the Kh18N(10-25) steels magnetic susceptibility at T=4.2-300 K, as well as its variation under the influence of elastic tension stresses at T=4.2, 77 and 300 K has been researched. It is concluded that these steels belong to the amorphous magnetic substances - myxomagnetics. Detected has been the magneto-elasticity phenomenon, which is inherent to the magnetic substances with a far-off magnetic order.
BibTeX: @article{Bol'shutkin198050, author = {Bol'shutkin, D. N. and Desnenko, V. A. and Il'yichev, V. Ya.}, title = {Magnetic susceptibility of steels Kh18N(10-25) in the range 4.2-300 K}, journal = {Physics of Metals and Metallography}, year = {1980}, volume = {49}, number = {2}, pages = {50-55}, note = {cited By 1}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0019111671&partnerID=40&md5=f327ce6fef6f4b1325817ed00c8c6a13} }
Grechnev G.E., Svechkarev I.V., J.W. M.	Magnetic properties and energy spectrum of Cd[1-x]Mg[x] alloys [Abstract] [BibTeX]	1980	Fizika Nizkikh Temperatur Vol. 6(3), pp. 324-331	URL
Abstract: Magnetic properties of the Cd[1-x]Mg[x] alloys are analyzed using the magnetism theory of conduction electrons suggested by Fukuhama as well as the model kxp hamiltonian. The experimental information on the effect of admixture scattering on the peculiarities of magnetic susceptibility is also used. Calculations of magnetic susceptibility are compared with experimental data. Parameters of the energy spectrum of pure cadmium are determined. They agree well with the results of direct spectrum calculation in the framework of the model of non-local Stark-Auluk pseudopotential. The behaviour of spectrum parameters during the introduction of isovalent (up to 12 at% of magnesium) in the range of low temperatures (T approximately equal to 20 K) is determined.
BibTeX: @article{grechnev1980, author = {Grechnev, G. E. and Svechkarev, I. V. and McCLURE J.W.}, title = {Magnetic properties and energy spectrum of Cd[1-x]Mg[x] alloys}, journal = {Fizika Nizkikh Temperatur}, year = {1980}, volume = {6}, number = {3}, pages = {324-331}, url = {https://inis.iaea.org/search/search.aspx?orig_q=RN:13644677} }
Fil V.	Electronic mechanism of acoustic-pulse transfer in magnetic fields [BibTeX]	1979	Soviet Physics - Uspekhi Vol. 22(6), pp. 478	DOI
BibTeX: @article{Fil1979478, author = {Fil, V.D.}, title = {Electronic mechanism of acoustic-pulse transfer in magnetic fields}, journal = {Soviet Physics - Uspekhi}, year = {1979}, volume = {22}, number = {6}, pages = {478}, doi = {http://dx.doi.org/10.1070/PU1979v022n06ABEH005579} }
Masalitin E., Fil' V., Gorborukov P.	Frequency-tunable automatic acoustic bridge [BibTeX]	1979	Measurement Techniques Vol. 22(11), pp. 1384-1386	DOI
BibTeX: @article{Masalitin19791384, author = {Masalitin, E.A. and Fil', V.D. and Gorborukov, P.M.}, title = {Frequency-tunable automatic acoustic bridge}, journal = {Measurement Techniques}, publisher = {Kluwer Academic Publishers-Plenum Publishers}, year = {1979}, volume = {22}, number = {11}, pages = {1384-1386}, doi = {http://dx.doi.org/10.1007/BF00827895} }
Bolshutkin D.N., Desnenko V.A., Ilichev V.Y.	Low temperature plastic deformation of FeCrNi steels in magnetic fields to 2.71 × 10³ Am^-1 [Abstract] [BibTeX]	1979	Cryogenics Vol. 19(4), pp. 231-234	DOI
Abstract: The low temperature (T=4.2 K) plastic deformation of stainless FeCrNi steels (18Cr8Ni, 18Cr10Ni, 18Cr15Ni, 18Cr20Ni and 18Cr25Ni) has been studied in constant (H = 2.71 × 103 Am-1) and transient magnetic fields (H ≤ 2.71 × 103 Am-1) changing exponentially in time at different rates. It is stated that the constant magnetic field of 2.71 × 103 Am-1 does not influence the tensile properties and plastic deformation of steels, but the transient magnetic fields lead to changes in deforming stress. The conclusion is made that the effects observed are due to the linear magnetostriction of steels and the Joule heating by eddy currents.
BibTeX: @article{Bolshutkin1979231, author = {Bolshutkin, D. N. and Desnenko, V. A. and Ilichev, V. Ya.}, title = {Low temperature plastic deformation of FeCrNi steels in magnetic fields to 2.71 × 10³ Am^-1}, journal = {Cryogenics}, year = {1979}, volume = {19}, number = {4}, pages = {231-234}, note = {cited By 3}, doi = {http://dx.doi.org/10.1016/0011-2275(79)90024-9} }
Grechnev G.E., Svechkarev I.V., Sereda Y.P.	Anomalous temperature dependence of the magnetic susceptibility of beryllium [Abstract] [BibTeX]	1978	Journal of Experimental and Theoretical Physics Vol. 48(3), pp. 502-505	URL
Abstract: The temperature dependence of the magnetic susceptibility of single-crystal beryllium is investigated in the temperature interval 4.2-1500 K and is theoretically interpreted. An anomalously high maximum of the diamagnetism is observed in the basal plane at T = 870 K and is due to the approach of the chemical-potential level to the point of band degeneracy on the line 2. The temperature-induced changes of the parameters of the beryllium spectrum near the band degeneracy point and the corresponding dependences of the susceptibility on the chemical-potential levels are calculated for various temperatures in a model with a nonlocal psuedopotential and an isotropic Debye-Waller factor. Comparison of these calculations with experiment yielded the position of the chemical potential level relative to the degeneracy point in the interval 500 < T < 1300 K .
BibTeX: @article{grechnev1978, author = {Grechnev, G. E. and Svechkarev, I. V. and Sereda, Yu. P.}, title = {Anomalous temperature dependence of the magnetic susceptibility of beryllium}, journal = {Journal of Experimental and Theoretical Physics}, year = {1978}, volume = {48}, number = {3}, pages = {502-505}, url = {http://www.jetp.ac.ru/cgi-bin/e/index/e/48/3/p502?a=list} }
Svechkarev I., Kuz'micheva L., Paltoratskii V.	Magnetic properties of zinc and of cadmium alloys with magnesium and with mercury [Abstract] [BibTeX]	1977	Sov J Low Temp Phys Vol. 3(5), pp. 323-330	URL
Abstract: A study was made concerning the magnetic susceptibility of single crystals of binary cadmium-magnesium and cadmium-mercury alloys, within the range of existence of disordered solid solutions and of ternary cadmium-magnesium-mercury alloys, the temperature-susceptibility characteristics of these alloys over the 4. 2-300 degree K range, and also the effect of uniaxial elastic strains and dislocations on the anisotropy of the magnetic susceptibility of zinc. From the anomalies of the magnetic susceptibility the locations of the critical points in the cadmium spectrum were then determined, and the separation between bands responsible for the magnetic properties was calculated. The nature of the influence which the temperature and the impurities have on the structure of the cadmium spectrum is analyzed here, and the scattering of electrons by the mercury impurity is evaluated.
BibTeX: @article{Svechkarev1977323, author = {Svechkarev, I.V. and Kuz'micheva, L.B. and Paltoratskii, V.I.}, title = {Magnetic properties of zinc and of cadmium alloys with magnesium and with mercury}, journal = {Sov J Low Temp Phys}, year = {1977}, volume = {3}, number = {5}, pages = {323-330}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0017490639&partnerID=40&md5=8baa60fe85e4086dd2905969d12e3c48} }
Svechkarev I., Sokoland O., Kuz'micheva L.	Magnetic susceptibility of lithium-magnesium alloys [Abstract] [BibTeX]	1977	Sov J Low Temp Phys Vol. 3(2), pp. 77-81	URL
Abstract: The magnetic susceptibility of body-centered cubic lattice solid solutions of lithium with magnesium is investigated. A model analysis is carried out of the susceptibility and its temperature dependence. Data are obtained about the behavior of the electron spectra parameters, the exchange enhancement properties of spin paramagnetism and the scattering of electrons in the lithium-magnesium system.
BibTeX: @article{Svechkarev197777, author = {Svechkarev, I.V. and Sokoland, O.M. and Kuz'micheva, L.B.}, title = {Magnetic susceptibility of lithium-magnesium alloys}, journal = {Sov J Low Temp Phys}, year = {1977}, volume = {3}, number = {2}, pages = {77-81}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0017453160&partnerID=40&md5=a57620c699083b762cb40db610b27f15} }
Vorontsov S., Dolgopolov D., Poltoratskii V., Svechkarev I.	Magnetic susceptibility anisotropy of holes in tellurium [Abstract] [BibTeX]	1977	physica status solidi (b) Vol. 83(1), pp. 341-346	DOI
Abstract: An expression for the spin contribution to the magnetic susceptibility anisotropy of holes in tellurium is derived. The total hole susceptibility anisotropy including spin and orbital terms is calculated with scattering taken into account. The complete quantitative description of the experimental data for hole concentrations of 3.5 × 1016 ≦ n < 3.5 × 1018 cm−3 and T = 4.2 K is obtained by means of selection and more precise definition of the spectrum parameters which determine the spin contribution. The discrepancy between calculated and experimental temperature dependences of the hole magnetic susceptibility anisotropy at temperatures above 60 K appears to be due to the thermal variation of the spectrum parameters.
BibTeX: @article{Vorontsov1977341, author = {Vorontsov, S.A. and Dolgopolov, D.G. and Poltoratskii, V.I. and Svechkarev, I.V.}, title = {Magnetic susceptibility anisotropy of holes in tellurium}, journal = {physica status solidi (b)}, year = {1977}, volume = {83}, number = {1}, pages = {341-346}, doi = {http://dx.doi.org/10.1002/pssb.2220830138} }
Vorontsov S., Svechkarev I.	Magnetic susceptibility of a two-dimensional crystal [Abstract] [BibTeX]	1977	Sov J Low Temp Phys Vol. 3(2), pp. 97-99	URL
Abstract: The orbital magnetic susceptibility has been determined for strictly two-dimensional motion of the conduction electrons in a layered structure. Such electrons correspond to cylindrical Fermi surfaces, i. e. , the energy spectrum contains no component of the wave vector perpendicular to the layers. Expressions have been derived for the major contributions to the susceptibility for certain types of perturbation in a parabolic spectrum due to Bragg planes. Results are presented from a numerical calculation on the effects of the chemical-potential level on the orbital and spin susceptibilities for the case where there is one plane, which show that there are sharp features at the critical points in the spectrum.
BibTeX: @article{Vorontsov197797, author = {Vorontsov, S.A. and Svechkarev, I.V.}, title = {Magnetic susceptibility of a two-dimensional crystal}, journal = {Sov J Low Temp Phys}, year = {1977}, volume = {3}, number = {2}, pages = {97-99}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0017453353&partnerID=40&md5=afe6a9e289d38d23c09051148b1f7a6f} }
Grechnev G.E., Svechkarev I.V.	Effect of energy spectrum features on the orbital magnetism in beryllium [Abstract] [BibTeX]	1977	Fizika Nizkikh Temperatur Vol. 3(6), pp. 770-777	URL
Abstract: The contributions to the orbital susceptibility of beryllium coming from the weakly splitted states located near the Fermi level has been calculated. It is shown that the temperature dependence of the susceptibility is determined by the states on the thin horizontal necks of the hole Fermi surface in the second band. The numerically calculated temperature dependence of the susceptibility is in a fair agreement with experiment.
BibTeX: @article{grechnev1977, author = {Grechnev, G. E. and Svechkarev, I. V.}, title = {Effect of energy spectrum features on the orbital magnetism in beryllium}, journal = {Fizika Nizkikh Temperatur}, year = {1977}, volume = {3}, number = {6}, pages = {770-777}, url = {http://fnte.ilt.kharkov.ua/fnt/pdf/3/3-6/f03-0770r.pdf} }
Fil V., Denisenko V., Bezuglyi P., Pirogov A.	Nonlinear absorption of sound in superconductors [Abstract] [BibTeX]	1976	Sov J Low Temp Phys Vol. 2(12), pp. 733-741	URL
Abstract: The experimental results are given of investigations of nonlinear effects in the absorption of sound in superconductors. The analysis carried out shows that the data obtained cannot be explained without taking into consideration the concept of increase of the energy gap of the superconductor under the action of high-powered ultrasonic pumping. The applicability of the various mechanisms of stimulation are discussed for explaining the observed nonlinearity.
BibTeX: @article{Fil1976733, author = {Fil, V.D. and Denisenko, V.I. and Bezuglyi, P.A. and Pirogov, A.S.}, title = {Nonlinear absorption of sound in superconductors}, journal = {Sov J Low Temp Phys}, year = {1976}, volume = {2}, number = {12}, pages = {733-741}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0017213976&partnerID=40&md5=32c62c92898fa79cdd89846754756a65} }
Manchenko V.N., Panfilov A.S., Svechkarev I.V.	Effect of pressure on magnetic-susceptibility of ternary palladium alloys containing rhodium and silver [Abstract] [BibTeX]	1976	ZHURNAL EKSPERIMENTALNOI I TEORETICHESKOI FIZIKI Vol. 71(12), pp. 2126-2130	URL
Abstract: The magnetic susceptibility of ternary alloys of palladium with rhodium and silver was measured at room temperature and under hydrostatic pressures up to 4000 atm. The effect of pressure on the structure of the spectrum and the effect of the electron scattering in the alloys are considered within the frameworks of simple models. An analysis of the experimental results for the ternary alloys and for the previously investigated binary alloys yields the parameters that describe the scattering, as well as the dependence of the density of the electronic states at the Fermi level and of the exchange enhancement of spin paramagnetism on the atomic volume.
BibTeX: @article{manchenko1976, author = {Manchenko, V. N. and Panfilov, A. S. and Svechkarev, I. V.}, title = {Effect of pressure on magnetic-susceptibility of ternary palladium alloys containing rhodium and silver}, journal = {ZHURNAL EKSPERIMENTALNOI I TEORETICHESKOI FIZIKI}, publisher = {MEZHDUNARODNAYA KNIGA}, year = {1976}, volume = {71}, number = {12}, pages = {2126-2130}, note = {Sov. Phys. JETP, Vol. 44, Number 6, pp. 1118-1120}, url = {http://www.jetp.ac.ru/cgi-bin/dn/e_044_06_1118.pdf} }
Bol'shutkin D.N., Desnenko V.A., Il'ichev V.Y.	Low-temperature plastic deformation of nickel in magnetic fields up to 34 kOe [Abstract] [BibTeX]	1976	Sov J Low Temp Phys Vol. 2(2), pp. 129-132	URL
Abstract: Low-temperature (T = 4.2 K) plastic deformation in polycrystalline nickel has been studied in constant (H = 34 kOe) and transient (H <= 34 kOe) magnetic fields which change exponentially in time at different rates. It has been established that a constant magnetic field H = 34 kOe increases the flow limit of nickel by about 10% while transient magnetic fields cause a change in the deforming stress. It is concluded that the observed effects can be explained by magnetostriction and Joule heating of the nickel samples by Eddy currents.
BibTeX: @article{Bol'shutkin1976129, author = {Bol'shutkin, D. N. and Desnenko, V. A. and Il'ichev, V. Ya.}, title = {Low-temperature plastic deformation of nickel in magnetic fields up to 34 kOe}, journal = {Sov J Low Temp Phys}, year = {1976}, volume = {2}, number = {2}, pages = {129-132}, note = {cited By 1}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0016924509&partnerID=40&md5=68998e8d853c7533577a354e5367adb2} }
Bol'shutkin D.N., Desnenko V.A., Il'ichev V.Y.	Magnetoplastic effect and heating by Eddy currents [Abstract] [BibTeX]	1976	Sov J Low Temp Phys Vol. 2(12), pp. 752-756	URL
Abstract: The effect of an alternating magnetic field on the plastic deformation of nickel and aluminum was examined at 4.2, 77, and 300 K, and the energy loss due to eddy currents was measured at 77 K only. It has been found that the characteristics of metal softening in an alternating magnetic field, the magnetoplastic effect, can be fully attributed to the temperature increase due to Joule heating by eddy currents.
BibTeX: @article{Bol'shutkin1976752, author = {Bol'shutkin, D. N. and Desnenko, V. A. and Il'ichev, V. Ya.}, title = {Magnetoplastic effect and heating by Eddy currents}, journal = {Sov J Low Temp Phys}, year = {1976}, volume = {2}, number = {12}, pages = {752-756}, note = {cited By 0}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0017203893&partnerID=40&md5=470d7e5b9e1c08713f6947cd6bc6ed98} }
Pivovar T., Svechkarev I., Gel'd P., Zagryazhskiy V.	Influence of pressure on the magnetic susceptibility of solid solutions V//3Si//1// minus //xGe//x [Abstract] [BibTeX]	1975	Physics of Metals and Metallography Vol. 40(5), pp. 167-171	URL
Abstract: From a comparison of these materials with the pure metals the band broadening is near to the standard, and less for vanadium metal. The relative shifts of the density of states of different symmetry at the Fermi level is apparently less than for d-metals of the same valency. However, due to the sharpness of the peak at the change in the density of states, this mechanism proves to be less effective than simple band broadening. The parameters found may be of interest, not only for correcting the lattice potential, but also in ascertaining the role of the band structure in the superconductive properties of A-15 compounds, and also for analysing the reasons for the spectral diffuseness in solid solutions of these compounds.
BibTeX: @article{Pivovar1975167, author = {Pivovar, T.L. and Svechkarev, I.V. and Gel'd, P.V. and Zagryazhskiy, V.L.}, title = {Influence of pressure on the magnetic susceptibility of solid solutions V//3Si//1// minus //xGe//x}, journal = {Physics of Metals and Metallography}, year = {1975}, volume = {40}, number = {5}, pages = {167-171}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0016673703&partnerID=40&md5=52889ca2e4d2d33a61bbbb5a1c7280d1} }
Svechkarev I., Poltoratskii V., Mar'yanina L.	Magnetic susceptibility of copper and silver [Abstract] [BibTeX]	1975	Sov Phys Solid State Vol. 17(7), pp. 1299-1302	URL
Abstract: A model calculation of the orbital magnetic susceptibility and its derivatives with respect to electron concentration was carried out for copper and silver alloys by using the method of summing the perturbations from the main Bragg planes. Comparison with the known experimental results shows that the calculation is satisfactory. Values of the ionic contributions and of the susceptibility of the matrix are derived from the analysis, and the effect of nonrigid bands is distinguished in alloys of copper and silver with simple metals. This effect is due to the interaction of the d band with the energy gap in the electronic spectrum of the matrix.
BibTeX: @article{Svechkarev19751299, author = {Svechkarev, I.V. and Poltoratskii, V.I. and Mar'yanina, L.F.}, title = {Magnetic susceptibility of copper and silver}, journal = {Sov Phys Solid State}, year = {1975}, volume = {17}, number = {7}, pages = {1299-1302}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0016628465&partnerID=40&md5=566a7b0aa7ec0082e1f2ae1b1fef04ba} }
Zhukov V., Svechkarev I., Kasowski R., Schone H.	Cadmium alloys band structure peculiarities from the NMR data [BibTeX]	1975	Magnetic resonance and related phenomena (Book), pp. 359	URL
BibTeX: @book{Zhukov1975359, author = {Zhukov, V.V. and Svechkarev, I.V. and Kasowski, R.V. and Schone, H.E.}, title = {Cadmium alloys band structure peculiarities from the NMR data}, journal = {Magnetic resonance and related phenomena (Book)}, publisher = {Am Elsevier Publ Co, Inc, New York, NY}, year = {1975}, pages = {359}, url = {https://inis.iaea.org/search/searchsinglerecord.aspx?recordsFor=SingleRecord&RN=6211344} }
Panfilov A.S., Pivovar T.L., Svechkarev I.V., Geld P.V., Sidorenko F.A.	Effect of pressure on magnetic-susceptibility of FeSi-CrSi and FeSi-NiSi monosilicide solid-solutions [Abstract] [BibTeX]	1975	ZHURNAL EKSPERIMENTALNOI I TEORETICHESKOI FIZIKI Vol. 68(6), pp. 2134-2138	URL
Abstract: The effect of hydrostatic pressure on the magnetic susceptibility of iron monosilicide and of some solid solutions based on it is investigated at room temperature. The derivatives with respect to volume are derived, within the framework of a simple model, for the inain parameters of the FeSi electron spectrum (energy gap and band width). The possible role of the disordering of the potential in solid solutions is assessed.
BibTeX: @article{panfilov1975, author = {Panfilov, A. S. and Pivovar, T. L. and Svechkarev, I. V. and Geld, P. V. and Sidorenko, F. A.}, title = {Effect of pressure on magnetic-susceptibility of FeSi-CrSi and FeSi-NiSi monosilicide solid-solutions}, journal = {ZHURNAL EKSPERIMENTALNOI I TEORETICHESKOI FIZIKI}, publisher = {MEZHDUNARODNAYA KNIGA}, year = {1975}, volume = {68}, number = {6}, pages = {2134-2138}, note = {Sov. Phys. JETP, Vol. 41, Number 6, pp. 1068-1070}, url = {http://www.jetp.ac.ru/cgi-bin/dn/e_041_06_1068.pdf} }
Svechkarev I., Panfilov A.	Effects of Pressure on the Electronic Structure of Transition d‐Metals [BibTeX]	1974	physica status solidi (b) Vol. 63(1), pp. 11-50	DOI
BibTeX: @article{Svechkarev197411, author = {Svechkarev, I.V. and Panfilov, A.S.}, title = {Effects of Pressure on the Electronic Structure of Transition d‐Metals}, journal = {physica status solidi (b)}, year = {1974}, volume = {63}, number = {1}, pages = {11-50}, doi = {http://dx.doi.org/10.1002/pssb.2220630102} }
Fil' V., Bezuglyi P., Masalitin E., Denisenko V.	An apparatus for studying changes in ultrasonic attenuation and velocity [BibTeX]	1973	Cryogenics Vol. 13(12), pp. 726-728	DOI
BibTeX: @article{Fil'1973726, author = {Fil', V.D. and Bezuglyi, P.A. and Masalitin, E.S. and Denisenko, V.I.}, title = {An apparatus for studying changes in ultrasonic attenuation and velocity}, journal = {Cryogenics}, year = {1973}, volume = {13}, number = {12}, pages = {726-728}, doi = {http://dx.doi.org/10.1016/0011-2275(73)90189-6} }
Svechkarev I., Pluzhnikov V.	Pressure Effect on the Fermi Surface of Molybdenum, Tungsten, and Rhenium [Abstract] [BibTeX]	1973	physica status solidi (b) Vol. 55(1), pp. 315-320	DOI
Abstract: Employing the de Haas‐van Alphen effect, the behaviour of small cross‐sections of the Permi surface under pressure has been studied on Mo, W, and Re. The results are discussed in terms of a simple empirical model for spectrum changes under pressure. The model also involves the deformation of d‐band and its shift relative t o the s·p band. The possibility is shown of obtaining quantitative information on the behaviour under pressure of the fundamental parameters of the transition metal energy spectra on the basis of studying small cross‐sections of the Fermi surface.
BibTeX: @article{Svechkarev1973315, author = {Svechkarev, I.V. and Pluzhnikov, V.B.}, title = {Pressure Effect on the Fermi Surface of Molybdenum, Tungsten, and Rhenium}, journal = {physica status solidi (b)}, year = {1973}, volume = {55}, number = {1}, pages = {315-320}, doi = {http://dx.doi.org/10.1002/pssb.2220550132} }
Svechkarev I., Pluzhnmov V., Volkenshtein N., Startsev V., Boiko V.	Pressure Effect on Small Cross‐Sections of the Fermi Surface in Ruthenium, Osmium, and Iridium [BibTeX]	1973	physica status solidi (b) Vol. 55(1), pp. K5-K7	DOI
BibTeX: @article{Svechkarev1973K5, author = {Svechkarev, I.V. and Pluzhnmov, V.B. and Volkenshtein, N.V. and Startsev, V.E. and Boiko, V.V.}, title = {Pressure Effect on Small Cross‐Sections of the Fermi Surface in Ruthenium, Osmium, and Iridium}, journal = {physica status solidi (b)}, year = {1973}, volume = {55}, number = {1}, pages = {K5-K7}, doi = {http://dx.doi.org/10.1002/pssb.2220550152} }
Panfilov A.S., Svechkarev I.V.	Effect of pressure on magnetic susceptibility of titanium-vanadium and vanadium-chromium alloys [Abstract] [BibTeX]	1972	SOVIET PHYSICS JETP Vol. 34(3), pp. 580-582	URL
Abstract: The effect of hydrostatic pressure up to 4000 kg/ cm2 on the magnetic susceptibility of titaniumvanadium and vanadium- chromium alloys is investigated at room temperature. It is shown that deformation of the d- band is the main mechanism determining the behavior of the susceptibility under pressure.
BibTeX: @article{panfilov1972, author = {Panfilov, A. S. and Svechkarev, I. V.}, title = {Effect of pressure on magnetic susceptibility of titanium-vanadium and vanadium-chromium alloys}, journal = {SOVIET PHYSICS JETP}, publisher = {AMER INST PHYSICS}, year = {1972}, volume = {34}, number = {3}, pages = {580-582}, url = {http://www.jetp.ac.ru/cgi-bin/dn/e_034_03_0580.pdf} }
Pluzhnikov V., Svechkarev I.	Pressure Effect on the Fermi Surface of Molybdenum and Tungsten [BibTeX]	1971	physica status solidi (b) Vol. 43(1), pp. K55-K57	DOI
BibTeX: @article{Pluzhnikov1971K55, author = {Pluzhnikov, V.B. and Svechkarev, I.V.}, title = {Pressure Effect on the Fermi Surface of Molybdenum and Tungsten}, journal = {physica status solidi (b)}, year = {1971}, volume = {43}, number = {1}, pages = {K55-K57}, doi = {http://dx.doi.org/10.1002/pssb.2220430160} }
Dekhtyar I.Y., Panfilov A.S., Svechkarev I.V., Fedchenko R.G.	Influence of pressure on magnetic susceptibility of alloys of palladium with rhodium and silver [Abstract] [BibTeX]	1971	SOVIET PHYSICS JETP Vol. 33(1), pp. 185-187	URL
Abstract: The effect of hydrostatic pressures up to 4,000 kg/cm2 on the magnetic susceptibility at room temperature is investigated in alloys of palladium with rhodium and with silver, by the method of free suspension of the sample with an inhomogeneous magnetic field. The experimental results are discussed within the framework of a simple empirical description of the variation of the electron spectrum of transition metals under pressure, containing deformation of the d-band and a relative shift of the s- and d-states on the Fermi level.
BibTeX: @article{dekhtyar1971, author = {Dekhtyar, I. Y. and Panfilov, A. S. and Svechkarev, I. V. and Fedchenko, R. G.}, title = {Influence of pressure on magnetic susceptibility of alloys of palladium with rhodium and silver}, journal = {SOVIET PHYSICS JETP}, year = {1971}, volume = {33}, number = {1}, pages = {185-187}, url = {http://www.jetp.ac.ru/cgi-bin/dn/e_033_01_0185.pdf} }
Panfilov A.S., Svechkarev I.V.	Effect of pressure on magnetic susceptibility of vanadium-chromium and chromium-manganese alloys [Abstract] [BibTeX]	1971	SOVIET PHYSICS JETP Vol. 32(4), pp. 630-632	URL
Abstract: The effect of hydrostatic pressure of up to 4000 kg/cm2 at room temperature on the magnetic susceptibility of chromium-vanadium and chromium-manganese alloys is investigated. The experimental results can be satisfactorily explained within the framework of a proposed simple model of changes in the electron spectrum induced by hydrostatic pressure, in which d-band deformation and a relative shift of the s-and d-bands are assumed. Values of parameters describing both mechanisms are obtained.
BibTeX: @article{panfilov1971, author = {Panfilov, A. S. and Svechkarev, I. V.}, title = {Effect of pressure on magnetic susceptibility of vanadium-chromium and chromium-manganese alloys}, journal = {SOVIET PHYSICS JETP}, publisher = {AMER INST PHYSICS}, year = {1971}, volume = {32}, number = {4}, pages = {630-632}, url = {http://www.jetp.ac.ru/cgi-bin/dn/e_032_04_0630.pdf} }
Svechkarev I., Kuzimicheva L.	Electron Phase Transition Display in the Susceptibility of Cadmium Alloys [BibTeX]	1970	physica status solidi (b) Vol. 37(2), pp. K113-K115	DOI
BibTeX: @article{Svechkarev1970K113, author = {Svechkarev, I.V. and Kuzimicheva, L.B.}, title = {Electron Phase Transition Display in the Susceptibility of Cadmium Alloys}, journal = {physica status solidi (b)}, year = {1970}, volume = {37}, number = {2}, pages = {K113-K115}, doi = {http://dx.doi.org/10.1002/pssb.19700370256} }
Maryakhin A., Svechkarev I.	Parameters of the Local Pseudopotential of Cadmium [BibTeX]	1969	physica status solidi (b) Vol. 33(1), pp. K37-K39	DOI
BibTeX: @article{Maryakhin1969K37, author = {Maryakhin, A.A. and Svechkarev, I.V.}, title = {Parameters of the Local Pseudopotential of Cadmium}, journal = {physica status solidi (b)}, year = {1969}, volume = {33}, number = {1}, pages = {K37-K39}, doi = {http://dx.doi.org/10.1002/pssb.19690330163} }
Melnik V., Svechkarev I.	Cyclotron Resonance in Mercury [BibTeX]	1969	physica status solidi (b) Vol. 33(1), pp. K33-K35	DOI
BibTeX: @article{Melnik1969K33, author = {Melnik, V.L. and Svechkarev, I.V.}, title = {Cyclotron Resonance in Mercury}, journal = {physica status solidi (b)}, year = {1969}, volume = {33}, number = {1}, pages = {K33-K35}, doi = {http://dx.doi.org/10.1002/pssb.19690330162} }
Maryakhin A., Svechkarev I.	On the Pseudopotential Coefficients and Spin‐Orbit Coupling in Metallic Cadmium [BibTeX]	1967	physica status solidi (b) Vol. 23(2), pp. K133-K136	DOI
BibTeX: @article{Maryakhin1967K133, author = {Maryakhin, A.A. and Svechkarev, I.V.}, title = {On the Pseudopotential Coefficients and Spin‐Orbit Coupling in Metallic Cadmium}, journal = {physica status solidi (b)}, year = {1967}, volume = {23}, number = {2}, pages = {K133-K136}, doi = {http://dx.doi.org/10.1002/pssb.19670230248} }
Panfilov A.S., Svechkarev I.V.	Method of measuring susceptibility of weak-magnetic materials under pressure [BibTeX]	1967	Instruments and Experimental Techniques Vol. -(3), pp. 179-180	URL
BibTeX: @article{panfilov1967, author = {Panfilov, A. S. and Svechkarev, I. V.}, title = {Method of measuring susceptibility of weak-magnetic materials under pressure}, journal = {Instruments and Experimental Techniques}, year = {1967}, volume = {-}, number = {3}, pages = {179-180}, url = {https://publons.com/p/29077186/} }
Svechkarev I.V., Panfilov A.S.	Effect of pressure on the magnetic susceptibility of manganese and scandium [BibTeX]	1965	JETP Letters Vol. 2(11), pp. 313-314	URL
BibTeX: @article{svechkarev1965, author = {Svechkarev, I. V. and Panfilov, A. S.}, title = {Effect of pressure on the magnetic susceptibility of manganese and scandium}, journal = {JETP Letters}, year = {1965}, volume = {2}, number = {11}, pages = {313-314}, url = {http://www.jetpletters.ac.ru/ps/1608/article_24653.pdf} }

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