Skyrmion cyclotron resonance in ferrimagnets
Phys. Rev. B 113, 224414 – Published 3 June, 2026
DOI: https://doi.org/10.1103/2xwg-j99t
Abstract
The finite mass of a skyrmion in a ferrimagnet, which is determined by the exchange interaction between spins belonging to different ferrimagnetic sublattices, leads to a gyroscopic motion of skyrmions, which is conceptually similar to the electron cyclotron resonance (ECR) in metals. We show that it can be excited in a ferrimagnetic film by a spin current or microwaves. Similar to how the ECR permits measurement of the effective electron mass, the skyrmion cyclotron resonance (SCR) must permit unambiguous measurement of the skyrmion mass. The presence of massive skyrmions strongly influences the spectrum of spin excitations in a ferrimagnet. The dependence of the SCR frequency on parameters is computed for a TM/RE (transition-metal/rare-earth) ferrimagnet, using CoGd as an example. The cyclotron frequency exhibits a dip near angular momentum compensation, where it hybridizes with the ferromagnetic resonance. The skyrmion cyclotron mode is studied for individual skyrmions and for skyrmion lattices, where the effect must be strong enough to be observed in microwave and spin-current experiments.
