Thermally induced spin torque and domain wall motion in superconductor/antiferromagnetic insulator bilayers

TL;DR

This paper proposes a theoretical mechanism where thermal gradients in a superconductor/antiferromagnetic insulator bilayer induce spin currents that can efficiently move magnetic domain walls at high velocities, leveraging the superconductor's thermal response.

Contribution

It introduces a novel theoretical model demonstrating thermally induced spin torque-driven domain wall motion in superconductor/antiferromagnetic insulator bilayers, highlighting the role of spin-split superconductors.

Findings

Domain walls can move at velocities around 100 m/s due to thermal spin currents.

The mechanism relies on the giant thermal response of spin-split superconductors.

Uncompensated antiferromagnet interfaces are crucial for spin current absorption.

Abstract

We theoretically investigate domain wall motion in an antiferromagnetic insulator layer caused by thermally generated spin currents in an adjacent spin-split superconductor layer. An uncompensated antiferromagnet interface enables the two crucial ingredients underlying the mechanism - spin splitting in the superconductor and absorption of spin currents by the antiferromagnet. Treating the superconductor using the quasiclassical theory and the antiferromagnet via Landau-Lifshitz-Gilbert description, we find domain wall propagation along the thermal gradient with relatively large velocities $\sim 100$ m/s. Our proposal exploits the giant thermal response of spin-split superconductors in achieving large spin torques towards driving domain wall and other spin textures in antiferromagnets.