Projects and grants
Head of group,
Principal Research Scientist,
Senior Research Scientist,
Senior Research Scientist,
Junior Research Scientist
1st cat. Engineer
The area of scientific researches
Electronic properties of metals in normal and superconducting states.
Vortex lattice dynamics in type-II superconductors.
Magneto elasticity; phase transitions of different nature in solids.
Precision measurements of the elastic modules of single crystals.
The extremal dimensions of Fermi surfaces
of Al, Mo and Ga have been measured, the anisotropy of the energy gap
in superconducting In and Al has been determined.
The regimes of strong interaction
of electrons with sound waves have been investigated. It was found that the electronic
contribution to the dynamic modulus of elasticity of high-purity single crystals can reach about 10-15%.
For the first time the effects of ballistic electron
transport of elastic deformation have been detected. The method of precise measurement of extreme
Fermi moment with simultaneous determination of the sign of charge carriers (Ga) was developed on
this basis. The anisotropy of the velocity of the electron-electron relaxation in Al has been studied.
Nonlinear electron-acoustic interaction
in metals (the so-called pulse linearity) has been found.
New types of electron waves that characterized
y a linear dispersion law have been discovered and explored in metals: beam and
cyclotron waves, zero-sound, the concentration waves. The excitation of fast magneto-sonic
and Alven magneto-plasma waves has been performed in "good metals" at first. These
waves previously had been observed only in Bi.
For the first time in metals have been registered the following:
a) the electric potential connected with the longitudinal sound wave;
b) the inertial field accompanying the transverse sound waves. It is the acoustic
analog of the Stewart-Tolman effect. Essentially new acousto-electric method for studying the
dynamics of vortex lattices in type-II superconductors has been developed.
The behavior of the Magnus force has been studied and parameters of the
pinning potentials have been measured in borocarbides with its help. For
the first time during the long history of the question the Abrikosov vortex mass
(~ 10-17 g/cm, YB6) has been measured experimentally. It has appeared in two orders
of magnitude larger then current theoretical estimates.
The elastic modules of representative
compounds of families of double molybdates, cuprates, borocarbides, hexa- and
dodecaborides, ferroborates have been measured.
In particular, a huge anisotropy of elastic properties in the basal plane
of La2CuO4 single crystals was discovered. The evolution of the elastic characteristics,
accompanying phase transformations ferroelastic and magnetic nature
have been studied in detail for all of these compounds. A lot of these
phase transitions have been discovered at first. The corresponding phase
diagrams in the plane "magnetic field-temperature" have been constructed.
One of the major achievements of the department is
the development of experimental equipment which permits to carry out high-accuracy
measurements of sound velocity and attenuation in strongly absorbing medium.
Temperature range is 0,4-350 K, the magnetic field is up to 5.5 T. In particular,
the "nonius" method, suitable for measuring the sound velocity in samples
of sub-millimeter size, was created.
The international cooperation
Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
Korea Basic Science Institute, Daejeon 305-333, Korea.
Institute for Solid State Physics, Technical University Dresden, Dresden D-01069, Germany.