Phenomenology of Current-Induced Dynamics in Antiferromagnets

TL;DR

This paper develops a phenomenological theory for current-induced dynamics in antiferromagnets, describing how electrical currents influence magnetic domain walls and their motion, including effects of damping and torques.

Contribution

It introduces a comprehensive phenomenological framework capturing reactive and dissipative current-induced torques in antiferromagnets, extending the understanding of domain-wall dynamics.

Findings

Walker ansatz describes dc current-induced domain-wall motion without dissipation.

Domain-wall velocity is proportional to the ratio of dissipative torque to damping.

Current-driven domain walls acquire a net magnetic moment.

Abstract

We derive a phenomenological theory of current-induced staggered magnetization dynamics in antiferromagnets. The theory captures the reactive and dissipative current-induced torques and the conventional effects of magnetic fields and damping. A Walker ansatz describes the dc current-induced domain-wall motion when there is no dissipation. If magnetic damping and dissipative torques are included, the Walker ansatz remains robust when the domain-wall moves slowly. As in ferromagnets, the domain-wall velocity is proportional to the ratio between the dissipative-torque and the magnetization damping. In addition, a current-driven antiferromagnetic domain-wall acquires a net magnetic moment.