Department of magnetic phenomena physics

Department of Physics of Magnetism (VFMYA), led by Professor, Cor. Nano S.M. Ryabchenko , was created in 1995 on the basis of laboratory physics of magnetic phenomena of solid state electronics. In turn, this laboratory was created in 1983 from part of the staff of the resonances that before vidpochkuvalysya of Crystal Physics Department, headed by a professor, academician NAS of Ukraine A.F. Prihot'ko.

Division brings together experts from radiospektroskopichnyh (electron paramagnetic, ferromagnetic, antiferromagnetic, nuclear quadrupole resonance), magnetostatic (magnetization, magnetic susceptibility), magnetoelastic (magnetostriction) and magneto-optical (spectral studies of the magnetic field and optically detected magnetic resonance) studies of solids crystals. At the stage of acquiring skill in magnetic methods of research, leading the department participated in seminars radiospectroscopy organized professor Cor.

NAS of Ukraine, MF Deyhenom, consulted him and his employees were his considerable influence. So department emerged and evolved as the development of scientific school teaching. A.F. Prihot'ko at the intersection of scientific school Cor. Nano MF Deyhena. When the department has nonstructural laboratory theory of imperfect crystals (TNC), led by prof. Nano Sci. E.A. Pashitskii. This lab was created at the time theoretical physicist, prof. V.L. Vinetskym.

Magnetic resonance, magnetooptics, magnetoelastic phenomena in layered antiferromagnetics, magnetic and magnetooptic phenomena in semimagnetic semiconductors, magnetic phenomena in high-temperature superconductors.

Mainstreams of scientific researches:

  • Physical properties diluted magnetic (semimagnetic) semiconductors;
  • The properties of continuous and nanogranular magnetic thin films and nanoparticles.
    In some recent years, practically all directions of researches at the PMP department have been concentrated on the study of corresponding properties in the case of nanostructures;
  • Magnetic properties of high-temperature superconductors.

Major scientific results:

  • Experimental discovery of the giant spin splitting of electronic and excitonic bands in dilute magnetic semiconductors and its explanation by the action of the carrier – ion exchange interaction (A. V. Komarov, S. M. Ryabchenko, O. V. Terletsky, I. I. Zheru, R. D. Ivanchuk, (J. Exper and Theor. Phys., 73, 608, (1977) [Engl/ transl.: Sov. Phys. JETP, 46, 318 (1977)]). In 1979, the phenomenon of ferromagnetic ordering in dilute magnetic semiconductors with current carriers was theoretically predicted (E. A. Pashitsky, S. M. Ryabchenko, Fiz. Tverd. Tela, 21, 545 (1979) [Engl. transl.: Sov. Phys. Sol. State, 21, 322 (1979)]). Representations about the role of spin correlations at the formation of magnetic polarons were advanced (S. M. Ryabchenko, Yu. G. Semenov, J. Exp. and Theor. Phys, 84, 1419 (1983)) at the beginning of the 1980s.
  • Establishment of the manifestations of magnetic and/or elastic quasi-twodimensionality in the magneto-resonance and relaxation properties of layered and quasi-2D crystals (A. F. Lozenko, S. M. Ryabchenko, State Prize of Ukraine in the field of Science and Engineering for 1991). In this circle of investigation, D. L. Lyfar’ and A. V. Bondar also took part.
  • Establishment of the magnetoelastic nature of antiferromagnetic domains in layered easy-plane antiferromagnets (V. M. Kalita, A. F. Lozenko, S. M. Ryabchenko, P. O. Trotsenko, Low Temp. Phys., 26, 489 (2000)).
  • Discovery of the basic laws for the temperature and magnetic – field dependences of critical current in thin epitaxial films of HTSC and their explanation as a result of the pinning of vortices by dislocations at the boundaries of monocrystalline blocks in the film (Yu. V. Fedotov, E. A. Pashitsky, S. M. Ryabchenko, A. V. Semenov // Low Temp. Phys., 2003. – 29, No. 8. – P. 630).
  • Establishment of the nature of low-field positive magneto-resistance in nanogranular magnetic films with the perpendicular anisotropy of granules (V. M. Kalita, A. A. Timopheev, A. F. Lozenko, S. M. Ryabchenko, A. V. Los, J. Appl. Phys., 110, 113918 (2011) ) and other effects in the nanogranular films.

  • It is found that the Zeeman oscillations of the NQR spin echo of 63Cu and 65Cu nuclei in HTSC compounds contains the information about magnetic fields of vortexes distribution in this materials. It is shown that the range of magnetic fields which generate the Zeeman oscillation in the NQR spin echo depends on the sequence of cooling and magnetization procedures.
  • The effect of unusually strong asymmetry in positions of the exciton spin-splitting components in the cubic semimagnetic semiconductor (SMS) Cd1-xCoxTe was detected for the first time. It is shown that this peculiarity of excitonic giant spin splitting (GSS) in cubic SMS connected with the manifestation of non- Heisenberg contribution to carrier-ion exchange interaction. The constants of the Heisenberg and non-Heisenberg carrier-ion exchange interaction was determined in SMS Cd1-xCoxTe.
  • It was proposed the separate description of the effects of a carrier-ion exchange interaction for the different valence subbands of Cd1-xMnxS SMS crystals, where carriers of A-valence subband can’t described by the mean-field approximation due to a large probability of their multiple scattering on Mn2+ ions. It is pointed out that mean-field approximation may be successfully realized for B-subbands carriers. The proposed model are experimentally checked by the study of the giant spin splitting of the B exciton for the magnetic field direction both along and across the crystal c axis. The analysis of the spin-splitting values is shown, that the parameters 1, 2 and 3 of valence band splitting of CdS crystals correspond to a model with the negative sign of the 1-2 difference. Since the many of results on the CdS optical properties were described with a help of a positive 1-2 difference, the interpretation of some of the earlier results may require reconsideration.
  • Paramagnetic enhancement of GSS of excitonic states in the quantum wells in the heterostructure of Cd1-xMnxTe/CdTe/Cd1-xMnxTe with different widths (Lw=12, 28, 60 and 120 A) was observed. It is proposed the simple procedure for describe of the magnetic and structural properties of interfaces Cd1- xMnxTe/CdTe and effect GSS in such structures.
  • V.G.Abramishvili,A.V.Komarov,S.M.Ryabchenko,A.I.Savchuk,Yu.G.Semenov. Carrier-ion exchange interaction in crystals Cd1-xCoxTe. //Solid State Communication. v.101,No.6,pp.397-402.(1997).
  • V.G.Abramishvili, A.V.Komarov, S.M.Ryabchenko, Yu.G.Semenov. Magnitooptical investigations of diluted Cd1-xMnxS magnetic semiconductors in the B-exciton region. // Physical Review. B, v.56, No.4, pp.1868 - 875.(1997).
  • А.В.Бондарь,Ю.В.Федотов.Зееман-эффект в ЯКР YBa2Cu3O7-x. // ФНТ, т.22, No1,с.62-66, (1996).
  • А.В.Бондарь, С.М.Рябченко,Ю.В.Федотов. Исследование внутренних магнитных полей в YBa2Cu3O7-x и Bi 2212 методом ЯКР. //ФНТ, т.22, №11, с.1337-1339,(1996).
  • В.М.Калита, А.Ф.Лозенко. Проявление негейзенберговских взаимодействий в температурной зависимости частоты ЯМР кристалла NiCl2. // ФНТ,т.23, №4,с.399-401,(1997).
  • St.n.s. A. Bondar measured spectra of spin echo NQR.

  • Work on Encyclopedia in an informal setting. Editorial Board Members (left to right) E.A. Pashitskii, O.H. Galkin,
    S. Ryabchenko clarifies the issue in V.M. Loktev while visiting prof. V.M. Pan at the Institute of Metal.

  • St.n.s. A.F. Lozenko and P.A. Trotsenko
    near vibration magnetometers.

  • The theory of "three." Staff LTNK: st.n.s. O.H. Galkina, SSF O. Semenov, jsw V.I. Pentehov.

  • Collective photo of department