Direct and inverse spin-orbit torques in antiferromagnetic and ferromagnetic FeRh/W(001)

TL;DR

This study uses ab-initio calculations to analyze spin-orbit torques in FeRh/W(001), revealing phase-dependent behaviors that could enable magnetic switching and current induction at resonance in both antiferromagnetic and ferromagnetic states.

Contribution

It provides the first detailed ab-initio comparison of spin-orbit torques in both antiferromagnetic and ferromagnetic phases of FeRh on W(001).

Findings

Antiferromagnetic phase exhibits a staggered effective magnetic field suitable for switching.

In the ferromagnetic phase, both even and odd SOT components are predicted.

SOTs in Fe/W(001) are also computed for the c(2×2) AFM state.

Abstract

We use \textit{ab-initio} calculations to investigate spin-orbit torques (SOTs) in FeRh(001) deposited on W(100). Since FeRh undergoes a ferromagnetic-antiferromagnetic phase transition close to room temperature, we consider both phases of FeRh. In the antiferromagnetic case we find that the effective magnetic field of the even torque is staggered and therefore ideal to induce magnetization dynamics or to switch the antiferromagnet (AFM). At the antiferromagnetic resonance the inverse SOT induces a current density, which can be determined from the SOT. In the ferromagnetic case our calculations predict both even and odd components of the SOT, which can also be used to describe the ac and dc currents induced at the ferromagnetic resonance. For comparison we compute the SOTs in the c($2\times 2$) AFM state of Fe/W(001).