Micromagnetic understanding of switching and self-oscillations in ferrimagnetic materials

摘要

Ferrimagnetic materials (FiMs) represent a promising direction for the realization of spin-based devices since they can combine the ultrafast dynamics typical of antiferromagnets in an easier way to control the magnetic state typical of ferromagnets. In this work, we micromagneti-cally analyze the magnetization dynamics of a current-driving transition metal/rare earth ferrimagnet in a spin Hall geometry as a function of the uncompensation parameter of the angular moments of the two sublattices. We show that, for a uniaxial FiM, a self-oscillation is the only possible dynamical state at the angular momentum compensation point. We also find a finite discontinuity near the magnetization compensation point originated from the demagnetizing field, which controls the type of dynamics behind the switching. We finally show the effect of the interfacial Dzyaloshinskii-Moriya interaction on both the switching time and the self-oscillation frequency and amplitude.