Catálogo de publicaciones - libros

The influence of dynamical correlation effects on the magneto-optical properties of ferromagnetic Fe and Ni has been investigated. In addition the temperature dependence of the self-energy and its influence on the DOS and optical conductivity is considered. Magneto-optical properties were calculated on the basis of the one-particle Green’s function, which was obtained from the DMFT-SPTF procedure. It is shown that dynamical correlations play a rather important role in weakly correlated Fe and substantially change the spectra for moderately correlated Ni. Magneto-optical properties obtained for both systems are found in better agreement with experiment than by conventional LDA calculations.

Starting from the assumption that ferromagnetically correlated regions exist in manganites even in the absence of long-range magnetic order, we construct a model of charge transfer due to the spin-dependent tunnelling of charge carriers between such regions. This model allows us to analyze the temperature and magnetic field dependence of resistivity, magnetoresistance, and magnetic susceptibility of phase-separated manganites in the temperature range corresponding to non-metallic behavior. The comparison of theoretical and experimental results reveals the main characteristics of the phase-separated state.

Fe-Tl, Co-Tl, Ni-Tl, and Mn-Tl chalcogenides are representatives of a new class of magnetic semiconductors. We propose a methods of synthesizing of TlMeB samples and present the results of investigations of electrical, thermoelectrical and magnetic properties of the prepared compounds.

The magnetic polaritons localized at the magnetic impurity layer in magnetic superlattice composed of the alternating ferromagnetic and nonmagnetic layers are investigated in the framework of the electromagnetic wave theory in the Voigt geometry. The general dispersion relation for localized magnetic polaritons is derived in the long-wavelength limit. The dispersion curves and frequency region of the exsistence of the localized magnetic polaritons for different parameters of the superlattices and magnetic impurities are calculated numerically and analysed.

LSDA non-relativistic frozen spin wave calculations reveal the presence of a non-uniform spin configuration in the ground state of SrRuO, characterized by a non-vanishing local spin moment on Ru hosts. This is related to nesting of the essentially two-dimensional Fermi surface. Spin instability at nesting vectors is manifested as a spin-density wave in the LSDA. By including the spin-orbit coupling, the magneto-crystalline anisotropy is estimated to be vanishingly small in spite of the layered structure of the system. On account of the small anisotropy, it is speculated that the zero-point fluctuations can destroy the staggered magnetization in this highly two-dimensional system. The static paramagnetic susceptibility is found to be slightly anisotropic dominating within tetragonal basal plane. The paramagnons intrinsically featured with phasons can tentatively be considered as a vague assessment for the lower part of excitation spectrum. As possible mediators for the superconductivity, the phasons reflect a specific symmetry of the ground state spinor: on an atomic scale the spinor symmetry is triplet, but on the scale of the helix the symmetry is a singlet. The obtained LDA results show the pure system is on the borderline between paramagnetism and non-uniform incommensurate antiferromagnetic instability.