Antiferromagnetic domain wall motion driven by spin-orbit torques

TL;DR

This paper presents a theoretical study showing that spin-orbit torques can efficiently drive antiferromagnetic domain walls at high speeds, leading to terahertz spin-wave emission and potential high-frequency signal generation.

Contribution

It introduces a theoretical framework for understanding antiferromagnetic domain wall dynamics driven by spin-orbit torques, highlighting their faster motion compared to ferromagnetic walls and the relativistic effects involved.

Findings

Antiferromagnetic domain walls move faster than ferromagnetic ones under spin-orbit torques.

Approaching maximum spin-wave velocity causes Lorentz contraction and spin-wave emission.

Potential for high-frequency terahertz signal generation in antiferromagnets.

Abstract

We theoretically investigate dynamics of antiferromagnetic domain walls driven by spin-orbit torques in antiferromagnet/heavy metal bilayers. We show that spin-orbit torques drive antiferromagnetic domain walls much faster than ferromagnetic domain walls. As the domain wall velocity approaches the maximum spin-wave group velocity, the domain wall undergoes Lorentz contraction and emits spin-waves in the terahertz frequency range. The interplay between spin orbit torques and the relativistic dynamics of antiferromagnetic domain walls leads to the efficient manipulation of antiferromagnetic spin textures and paves the way for the generation of high frequency signals in antiferromagnets.