Department of Low-Temperature Magnetism and Radio spectroscopy of Solids under High Pressures
Alternate head of the Department: Eduard E. Zubov,
candidate of physico-mathematical sciences, senior scientist
(062) 311-52-66
Directions of Scientific Researches: Investigation of magnetic and transport properties of manganites, magnetism of small-sized magneto-dielectrics and organic magnetics, magnetic and superconductive properties of HTSC.
Basic Results
For the time there has been induced a dielectric-superconductor transition in non-superconductive ceramics HTSC of 123 type. There have been studied the evolution of superconductivity in the process of oxygen ordering under pressure in non-superconductive ceramics LaBa2Cu3O6.74.
A structural phase transition of the Ian-Teller type was first detected in monocline double rare-earth tungstates.
There has been revealed an anomalous acoustic-electrical effect (AE) in a thin film of manganite La0.67Ca0.33MnO3deposited on a piezo-dielectric base. A theoretical analysis has shown that the anomalous acoustic-electrical effect is caused by a great modulation of the film conductivity because of deformation provoked by PAB. The theory results are in a good agreement with the experiment.
Acoustical surface and exchange spin-wave modes were first detected and studied in manganite films. There were determined critical angles and temperatures at which the surface and spin-wave modes had transformed into a homogeneous mode.
In crystals K(Dy+Y)(WO4)2 having 1 and 2% concentration of Dy there were detected the spectra of interacting ion pairs arranged in the first and second coordination spheres. There was done a theoretical analysis of the structure of the basic state in the model of a binary exchange with the reasoning of thermodynamic stability of a noncollinear ferromagnetism.
In manganite-lanthanum perovskites having an excess of manganese, there was detected a transition from a ferromagnetic into a beveled phase in clusters of unequally valence ions of manganese.
In the EPR spectra of organo-metallic complexes, there were detected two lines belonging to ion Fe3+ and having effective g-factors equal to 4.317 and 2.005.
Applied researches
Development of sensors to measure magnetic field, pressure and direct current on the base of manganites and ferrites using magneto resistive effect.
Scientific cooperation
The Institute of Physics of the Polish Academy of Sciences (Poland).
Selected publications
1 .M.T.Borowiec, V.Dyakonov, A.Jedrzejczak, V.Markovicz, A.Nabialek, A.Pavluk, S.Piechota, A.Prochorov, H.Szymczak. Jahn-Teller type structural transition in KDy(WO4)2. Solid State Communication 8 (102), 627 (1997).
2. V.Dyakonov, I.Fita, N.Doroshenko, M.Baran, S.Piechota, H.Szymczak. Insulator-superconductor transition in NdBa2Cu3O6.67 ceramics under pressure. Physica C, 3-4 (276), 245 (1997).
3. M.T.Borowiec, V.Dyakonov, A.Prohorov, H.Szymczak. Temperature variation of EPR spectra of Dy3 in single crystal KY(WO4)2. Physical Review B 62 (9), 5834 (2000).
4. Y.Ilisavskii, A.Goltsev, K.Dyakonov, V.Popov, E.Yakhind, V.P.Dyakonov, A.Klimov, S.Lewandovski, H.Szymczak. Anomalous acoustoelectric effect in (La0.7Ca0.3)1-xMn1+xO3 films. Physical Review Letters 87, 146602 (2001).
5. V.P.Dyakonov, A.Prokhorov, V.Shapovalov, V.Krivoruchko, V.Pashchenko, E.Zubov, V.Mikhajlov, P.Aleshkevich, M.Berkowski, S.Piechota, H.Szymczak. Surface and bulk spinwave resonances in La0.7Mn1.3O3. Journal of Physics: Condensed Matter 13, 4049 (2001).
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