Current-induced torques in continuous antiferromagnetic textures

TL;DR

This paper investigates how electric currents influence non-collinear antiferromagnetic textures, revealing that current-induced torques act similarly to those in ferromagnets despite the lack of net magnetization.

Contribution

It generalizes the non-linear sigma model to include current-induced torques in antiferromagnets and interprets these effects through an effective spin-orbit coupling framework.

Findings

Current-induced torques in antiferromagnets are phenomenologically similar to ferromagnets.

The generalized sigma model describes domain wall motion and spin-wave Doppler shift.

A unifying picture links these torques to current-induced spin polarization via effective spin-orbit coupling.

Abstract

We study the influence of an electric current on a continuous non-collinear antiferromagnetic texture. Despite the lack of a net magnetic moment we find that the exchange interaction between conduction electrons and local magnetization generally results in current-induced torques that are similar in phenomenology to spin transfer torques in ferromagnets. We present the generalization of the non-linear sigma model equation of motion for the N\'{e}\`{e}l vector that includes these current-induced torques, and briefly discuss the resulting current-induced antiferromagnetic domain wall motion and spin-wave Doppler shift. We give an interpretation of our results using a unifying picture of current-induced torques in ferromagnets and antiferromagnets in which they are viewed as due to the current-induced spin polarization resulting from an effective spin-orbit coupling.