Modeling Ferrimagnets in MuMax3: Temperature-Dependent Skyrmion Dynamics

Abstract: In this work, we propose an approach to modeling ferrimagnets in MuMax3. We show that by specifying two interacting magnetic sublattices as separate layers, it is possible to reproduce a sperimagnetic-like ordering of magnetization. In such a system, magnetic and angular momentum compensation states can be achieved only by varying the temperature while keeping other parameters fixed. This behavior arises from the different temperature dependencies of the magnetization projections in the sublattices, as determined by their thermal functions. We also investigated the motion of a skyrmion under the action of a spin-polarized current. By changing the temperature, we observed both the disappearance of the skyrmion Hall effect at the angular compensation point and the maximum velocity of translational motion. The latter effect requires a modified version of MuMax3 that allows the g-factor to be specified for different regions. The proposed approach can also be applied to study other phenomena in ferrimagnets, including the influence of composition on the magnetic and angular compensation temperatures, the tilted phase, domain-wall motion, and effects arising from non-uniform current or temperature distributions.