Fizika Nizkikh Temperatur: Volume 43, Number 12 (December 2017), p. 1715-1723 ( to contents , go back )
Spectra of collective excitations and the low-frequency asymptotic of Green’s functions of degenerate states of spin s = 1 magnets
A.V. Glushchenko, M.Y. Kovalevsky, and V.T. Matskevich
National Science Center “Kharkov Institute of Physics and Technology” 1 Akademicheskaya Str., Kharkov 61108, Ukrain
Received June 19, 2017
The paper describes the evolution of nonequilibrium degenerate states of one- and many-sublattice magnets with spin s = 1 in an external field. Dynamic equations for magnetic degrees of freedom have been obtained and low-frequency asymptotics of two-time Green's functions were calculated. The spectra of collective excitations in the states of a ferromagnet, a quadrupole magnet, and a spin nematic are found. A comparative analysis of these asymptotics is carried out and influence of the unitary symmetry of the exchange interaction on the character of the magnetic anisotropy is clarified.
PACS: 75.10.–b General theory and models of magnetic ordering.
Key words: spin, symmetry, dynamics, spectra of excitations, Green’s functions.
Published online: October 25, 2017