
Department of Theoretical Physics, Institute of Magnetism Fields of Research
Theory of Magnetism
 Kinetic theory of magnons, solitons and breathers in the integrable magnetic systems along with their kinetic coefficients are formulated.
 Theory of the exchange relaxation of nonlinear magnetic waves in ferromagnets is developed.  New methods to study the magnetic valve effect for layered magnetic structures are proposed. Modern problems of Solid State Physics
 Optimal methods to protect the Josephson analyzer head against to intensive electromagnetic radiation are proposed by means of magnetic and superconductor materials.
 Interaction effects of the intensive spin and electromagnetic waves in ferromagnets in vicinity of orientational phase transition are studied and the selffocusing and transverse modulation of electromagnetic waves is predicted in this case.  An influence of acoustic waves on the orientational phase transition is shown can change the type of the phase transition.  Statistical termodynamics, electronic and straininduced properties of the lattice systems with the longrange interatomic interactions. Elaboration of the methods for calculations of the interatomic interaction (force and energy) parameters of statisticalthermodynamic description of the lattice system on the basis of the electronic theory (within the cluster modelling by XaSW method and FLAPW method for the calculations of the electronic structure of solids) taking into account the lattice distortions caused by the impurity components of system. Calculations of the Fourier components of the interatomic potentials and straininduced effects in substitutional (e. g. FeCr), interstitial (e. g. FeN, FeC) and substitutionalinterstitial (FeCrN and FeCrC) alloys. Calculations of the shortrange order parameters and their Fourier components, configuration correlation radia for abovementioned alloys. Analysis of the relation between the structural and mechanical properties of Febased alloys. Elaboration of recommendations as for compositions.  Investigation of the electronic structure of complex oxides with the perovskite type structure. Interpretation of the experimental results (including XPS and X  ray emission and absorbtion spectra). HTS compounds (YBa_{2}Cu_{3}O_{7±d}); Compounds A_{1x}Me_{x}MnO_{3} (A=La,Pr; Me=Sr,Ca,K); Compounds ATiO_{3} (A=Ba,Pb); Superionics compounds La_{1x}Li_{x}TiO_{3}.  A new cluster method to calculate the thermodynamic potential of the Ising model is proposed. Mathematical Physics
 Theory of phase transition is formulated in terms of stable random variables by Levy.  A theory of addition of the Kleinian hyperelliptic functions is developed and then applied to the integrabilityproblem of nonlinear partial differential equations of evolution type  In the long Josephson junction a transmission of twophase nonlinear electromagnetic waves is studied and the appropriate voltampear characteristics are built by means of the Riemannian thetafunctions. Studies concerned with the Chernobyl catastrophe
 Program package, which realize multidimensional modeling methodology.  Tool for 3Dmathematical modelling which is founded on principles of selforganisation allow us to construct sufficiently reliable 3D models of different geochemical and geophysical parameters on data with real level noise. This can be, for instance, a regional 3D model of fields of radionuclei pollutions or distribution of other geophysical parameters. All these sources of information are being included, by applying different confidence weights. These weights must reflect the reliability of data. Arbitrarily oriented sections of the parameters distribution are rather conveniently extracted from 3D model. Thus, the model not only serves as a regional data base for parameters, but also provides a tool for deeper studying of multidimentional fields. This would be for instance especially useful for the making of right decisions during the liquidation of the consequences of global catastrophes, such as Chernobyl, which cause the contamination of environment. 

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