Institute for Low Temperature Physics and Engineering

DEPARTMENT OF SUPERCONDUCTIVITY

tel : +(380)-57-341-08-30
f ax: +(38)-057-340-33-70

E-mail: zolochevskii@ilt.kharkov.ua

Department was founded in 1968. Since then and until 2009 it was headed by Professor V.M.Dmitriev, a known scientist in the field of physics of superconductivity, Doctor of Physics & Mathematics, a holder of State Prize of Ukraine, Honored Worker of Science and Technology of Ukraine. At present I.V . Zolochevskii, Candidate of Science, senior researcher, is the acting head of the Department.

The Department staff includes: A.L. Soloviev, Doctor of Phys. & Math. Science and six Candidates of Phys.-Math. Sci.: A.M. Gurevich, I.V. Zolochevskii, V.N. Svetlov, L.F. Rybalchenko, A.V. Terekhov, and E.V. Khristenko.

Areas of research:
stationary and nonstationary, equilibrium and nonequilibrium electric and magnetic properties of superconductors, low-temperature phase transitions in solids.

Methods of research:
resistive, magnetic and resonance measurements in the temperature region 1.5-300 K in the frequency range up to 100 GHz in high magnetic fields, point -contact spectroscopy, Laser scanning microscopy, adiabatic calorimetry.

Main results:

  • The phenomenon of enhancement of superconductivity by external microwave irradiation was discovered and investigated experimentally.
  • The phenomenon of non-Josephson generation of electromagnetic oscillations by the phase-slip centers and lines in conventional superconductors was discovered and studied experimentally.
  • For the first time the phase-slip centers were visualized by the method of laser scanning imaging and their internal structure was studied experimentally. It was proved that they are a source of the non-Josephson generation.
  • The temperature and frequency dependences of the penetration depth of the longitudinal electric field in a superconductor was discovered and investigated.
  • The effect of a self-detection of centimeter wavelengths Josephson radiation by the superconducting film bridge deposited on the rutile resonator was found.
  • High-frequency phase-slip centers and lines, in the narrow and wide superconducting films respectively, which occur under external microwave irradiation was observed experimentally.
  • A new criterion for separation of conventional superconducting films into narrow and wide was formulated.
  • It was shown for the first time that on passing a transport direct current in a wide superconducting film two alternative mechanisms of resistivity caused by the motion of vortices and the phase-slip processes can operate in succession.
  • The role of the fluctuation contributions to the superconductivity of classical superconductors as well as to the formation of the pseudogap state in high-T C superconductors was convincingly cleared up.
  • For the first time the temperature dependence of surface impedance of superconducting MgB2 in the frequency range 9-110 MHz was investigated. The transition from the nonlocal Pippard limit to the local London limit near T C , predicted theoretically in 1958, was discovered experimentally (2004) .
  • Superconductivity and negative magnetoresistance in the RM4Al8 compounds (R - rare earth, M - transition metal) was discovered and investigated. It was shown that the superconducting transition temperature in LuFe4Al8 reaches T C = 25K.

At present the Department is engaged in intensive and comprehensive experimental investigations of magnetic superconductors.

It was shown for the first time that the Dy1-xYxRh4B4 compound is a ferrimagnet at T < 30.5K, a ferrimagnetic superconductor at T <5.9 K and undergoes an antiferromagnetic transition (without destruction of superconductivity) below 2.7 K. The Volleben effect was observed (positive response of the magnetization of the superconductor in the FC regime) in Dy1-xYx Rh4B4 (x = 0.2; 0.4) compounds in applied fields below 20 Oe. ( V.M. Dmitriev, A.J. Zaleski, E.P. Khlybov, A.V. Terekhov, L . F . Rybaltchenko , E . V . Khristenko , L . A . Ishchenko & A.V. Terekhov, Acta Physica Polonica , 2008, A114 , pp.83-90; V.M. Dmitriev, A.J. Zaleski, E.P. Khlybov, L . F . Rybaltchenko , E . V . Khristenko , L . A . Ishchenko, A.V. Terekhov, I. Å . Êî styleva, S. À . Lachenkov, Fiz. Nizk. Temp., 2008, v. 34 , ¹ 11, p. 1152-1162) .

For the first time the gap dependences Δ(T) and Δ(H) were investigated experimentally in Dy1-xYxRh4B4 at temperatures above and below the antiferromagnetic – ferromagnetic transition.

It is shown that this phase transition affects significantly the shape of the dependence Δ (T, H), which at T <2.7K differ significantly from conventional superconductors. Thus, there is a high probability of existence of unconventional mechanisms of superconducting pairing in Dy1-xYxRh4B4 ( V.M. Dmitriev, A.J.Zaleski, E.P. Khlybov, L . F . Rybaltchenko , E . V . Khristenko , L . A . Ishchenko, A.V. Terekhov, Fiz. Nizk. Temp., 2009, v. 35 , ¹5, p. 537-539)

Awards:
The State Prize of Ukraine in the field of science and technology for the series of works “Superconductivity enhanced by alternating electromagnetic field and phase-slip processes in thin films of superconductors including high-temperature ” (2000). Authors: E.V. Bezugly, V.G.Volotskaya, V.P.Galaiko, V.M.Dmitriev, I.M.Dmitrenko, I.V.Zolochevskii, A.G.Sivakov, E.V.Khristenko, G.E.Churilov

International cooperation:
International Laboratory of High Magnetic Fields and Low Temperatures, Wroclaw, Poland; Grenoble High Magnetic Field Laboratory, Centre National de la Recherche Scientifique , France; Max-Planck-Institut für Festkorperforschung, Germany; W. Trzebiatowski Institute Low Temperatures and Structure Research, Wroclaw, Poland