This article is cited in 15 papers

CONDENSED MATTER

Limiting velocity and dispersion law of domain walls in ferrimagnets close to the spin compensation point

E. G. Galkina^a, C. E. Zaspel^b, B. A. Ivanov^cd, N. E. Kulagin^edf, L. M. Lerman<sup>g

a</sup> Institute of Physics, National Academy of Sciences of Ukraine, Kyiv, 03028 Ukraine
^b Department of Environmental Sciences, University of Montana Western, Dillon, MT 59725, USA
^c Institute of Magnetism, National Academy of Sciences of Ukraine, Kyiv, 03142 Ukraine
^d National Research University of Science and Technology MISiS, Moscow, 119049 Russia
^e Moscow Aviation Institute (National Research University), Moscow, 125993 Russia
^f Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow, 119071 Russia
^g Lobachevsky National Research University of Nizhny Novgorod, Nizhny Novgorod, 603950 Russia

Abstract: The motion of domain walls in GdFeCo-type ferrimagnets near the point of compensation of sublattice spins $s_1$ and $s_2$, when the effects of the exchange increase in the limiting wall velocity take place, is theoretically studied. The energy $E$ and momentum $P$ of the wall are determined and the dispersion relation $E = E(P)$ is derived. It is found that some walls become unstable at a sufficiently small decompensation value $s_1-s_2<\nu_c(s_1+s_2)$, $\nu_c\ll1$, and the dispersion relation $E(P)$ has an end point at some finite momentum. At $s_1-s_2>\nu_c(s_1+s_2)$, this dispersion relation, as well as that for ferromagnets, is periodic.

Received: 24.06.2019
Revised: 26.08.2019
Accepted: 26.08.2019

DOI: 10.1134/S0370274X1919007X

 English version: Journal of Experimental and Theoretical Physics Letters, 2019, 110:7, 481–486

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