Bidirectional spin-wave-driven domain wall motion in antiferromagnetically coupled ferrimagnets

TL;DR

This paper explores how circularly polarized spin waves can induce bidirectional domain wall motion in ferrimagnets, with the direction depending on polarization and net spin density, offering a new method for magnetic control.

Contribution

It demonstrates theoretically and numerically that spin wave polarization and net spin density control domain wall motion direction in ferrimagnets, revealing a novel bidirectional driving mechanism.

Findings

Domain wall motion direction depends on spin wave polarization.

Reversal of motion occurs across the angular momentum compensation point.

Spin waves can serve as versatile bidirectional driving forces.

Abstract

We investigate ferrimagnetic domain wall dynamics induced by circularly polarized spin waves theoretically and numerically. We find that the direction of domain wall motion depends on both the circular polarization of spin waves and the sign of net spin density of ferrimagnet. Below the angular momentum compensation point, left- (right-) circularly polarized spin waves push a domain wall towards (away from) the spin-wave source. Above the angular momentum compensation point, on the other hand, the direction of domain wall motion is reversed. This bidirectional motion originates from the fact that the sign of spin-wave-induced magnonic torque depends on the circular polarization and the subsequent response of the domain wall to the magnonic torque is governed by the net spin density. Our finding provides a way to utilize a spin wave as a versatile driving force for bidirectional domain wall motion.