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Current issue   Ukr. J. Phys. 2014, Vol. 58, N 12, p.1149-1155
doi:10.15407/ujpe58.12.1149    Paper

Bar’yakhtar V.G.1, Ivanov B.A.1, Golubeva O.N.2, Sukhanov A.D.3

1 Institute of Magnetism, Nat. Acad. of Sci. of Ukraine and Ministry of Education and Science,
Youth and Sport of Ukraine
(36, Academician Vernadskyi Blvd., Kyiv 03680, Ukraine)
3 Peoples’ Friendship University of Russia
(3, Ordzhonikidze Str., Moscow, Russia)
3 Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research
(Dubna 141980, Russia)

Phenomenological Theory of Relaxation in Two-Sublattice Ferrite

Section: Solid matter
Original Author's Text: Ukrainian

Abstract: The dissipative function of a two-sublattice ferrite was constructed. The relaxation times for the acoustic and optical branches of spin waves are calculated, as well as the relaxation times for the magnetization and antiferromagnetism vectors. The process of antiferromagnetism vector relaxation is shown to be the quickest one. The corresponding relaxation time is governed by the exchange relaxation constant and, due to the exchange interactions between atoms in the sublattices, becomes shorter owing to the dynamics of the antiferromagnetism vector. The process of ferrite magnetization relaxation is the slowest one. In the exchange approximation, the magnetization relaxation time tends to infinity, as the length of magnetization non-uniformities grows. The results obtained are compared with the experimental data on the relaxation phenomenon in GdFeCo alloy of rare-earth and transition metals.

Key words: dissipative function of two-sublattice ferrite, relaxation times for the magnetization, relaxation times for the antiferromagnetism vector.