Klevets P. Dynamic properties and phase states of two-dimensional Heisenberg and non-Heisenberg magnetics.

The reorientation phase transitions (RPT) in 2D-ferromagnetic films, and the phase transitions and states of 2D-non-Heisenberg magnets are studied in dissertation. It is shown that RPT from the easy-axis phase to the plane one takes place through the canted phase in the model, which takes into account the influence of magnetodipole and magnetoelastic (ME) interactions, anisotropy depending on temperature. The estimations of canted phase existence temperature interval give about 105° К. It is established that the influence of ME interaction on the formation of domain phase is exhibited in increase of the field region of domain phase existence. The spectra of quasiparticles were obtained in non-Heisenberg ferromagnet for various types of ME interactions. It is shown that the quadrupole phase does not realize in isotropic non-Heisenberg antiferomagnets at any relations between exchange constants