Spin-transfer torques in anti-ferromagnetic metals from first principles

TL;DR

This paper presents a first principles study showing that anti-ferromagnetic metals exhibit significant, nonlocal spin-transfer torques capable of inducing magnetization dynamics, despite lacking a macroscopic magnetic moment.

Contribution

It provides the first detailed electronic transport analysis of anti-ferromagnetic systems, revealing comparable spin torques to ferromagnets and their potential for domain wall motion.

Findings

Spin torques in anti-ferromagnets are comparable to ferromagnets.

Spin torques are highly nonlocal in anti-ferromagnets.

Potential for current-induced domain wall motion in anti-ferromagnetic materials.

Abstract

In spite of the absence of a macroscopic magnetic moment, an anti-ferromagnet is spin-polarized on an atomic scale. The electric current passing through a conducting anti-ferromagnet is polarized as well, leading to spin-transfer torques when the order parameter is textured, such as in anti-ferromagnetic non-collinear spin valves and domain walls. We report a first principles study on the electronic transport properties of anti-ferromagnetic systems. The current-induced spin torques acting on the magnetic moments are comparable with those in conventional ferromagnetic materials, leading to measurable angular resistances and current-induced magnetization dynamics. In contrast to ferromagnets, spin torques in anti-ferromagnets are very nonlocal. The torques acting far away from the center of an anti-ferromagnetic domain wall should facilitate current-induced domain wall motion.