ELECTRONIC, MAGNETIC, AND SUPERCONDUCTING PROPERTIES OF METALS AND COMPOUNDS

Group members:
team leader - Senior researcher, Ph.D. Beliayev Eugeniy Yurievich;
junior researcher - Horielyi Vitaliy Alexandrovich.

Subjects of scientific researches:

1. The electronic transport properties of polycrystalline samples and thin films of the topological insulator Bi₂Se₃ are measured with the aim - to identify the differences in the surface and bulk transport properties of charge carriers.
2. Studying of the multicomponent compound - magnetic superconductor RuSr₂(Eu_1.5Ce_0.5)Cu₂O_10-δ. The relationships between magnetic, conducting and superconducting properties with a change in oxygen content are studied. The publication of article [1] is expected in which the electronic transport properties of this compound after the disappearance of superconductivity caused by the loss of stoichiometric oxygen are associated with the manifestation of the Kondo effect.
3. We continue the research cycle on granular pressed powder composites based on half metal CrO₂ nanoparticles coated with dielectric shells. In published works:
- the influence of the thickness and composition of the dielectric on the tunneling conductivity was analyzed [2];
- the mismatch of the coercity fields when measuring the magnetoresistance and magnetization hysteresis curves was discovered and explained on the basis of percolation effects [3, 4];
- the effect of Fe impurities on the tunneling conductivity in CrO₂composites at low temperatures is associated with the formation of localized states in the dielectric barrier [5];
- it was shown that the magnitude of the anisotropy of the tunnel magnetoresistance is determined by the difference in the magnitudes of the magnetic susceptibility along the light and heavy axes of magnetization [6].

The list of cited publications of our group (2017 – 2020):

1. Dalakova, N.V., Bludov, A.N., Beliayev, E.Yu., Horielyi, V.A., Osmolowskaya, O.M., Osmolowsky, M.G. Magnetic anisotropy and anisotropic tunneling magnetoresistance of compacted half-metal CrO2 nanopowders // Bulletin of the Russian Academy of Sciences: Physics, 81, Issue 3, Pages 278-281 (2017).
2. Kolesnichenko Yu.A., Dalakova N.V., Beliayev E.Yu., Bludov, O.M., Horielyi V.A., Osmolowskaya O.M., Osmolowsky M.G. Features of low-temperature tunneling magnetoresistance of pressed chromium dioxide CrO2 nanopowders // LTP, 43, Issue 5, Pages 617-624 (2017).
3. N.V. Dalakova, E.Yu. Beliayev, V.A. Horielyi, Coercive force in the system of ferromagnetic granules for half metal CrO2 with percolation conductivity // East European Journal of Physics V.4(3), P.78-84 (2017).
4. Dalakova N.V., Beliayev E.Yu., Horielyi V.A., Osmolowskaya O.M., Osmolowsky, M.G. Anomaly in the Temperature Dependence of the Coercive Force of an Ensemble of Ferromagnetic CrO2 Nanoparticles under Conditions of Percolation Conductivity // Bulletin of the Russian Academy of Sciences: PhysicsVolume 83, Issue 6, Pages 852-855 (2019).
5. Dalakova N.V., Beliayev E.Yu., Bludov A.N., Horielyi, V.A., Osmolowskaya, O.M., Osmolowsky, M.G. Conductivity of pressed powders of chromium dioxide with spin-dependent electron tunneling: The effect of thickness and composition of dielectric layers // LTP, 45, Issue 12, Pages 1514 – 1523 (2019).
6. Beliayev E.Yu., Horielyi V.A., Kolesnichenko Yu.A. Interplay of hopping conductivity and superconductivity in samples of magnetic superconductor RuSr₂(Eu_1.5Ce_0.5)Cu₂O_10-δ // Low Temperature Physics Volume 46, Issue 6, P. 584 (2020).