Spin Torque in Anisotropic Tunneling Junctions

TL;DR

This paper theoretically investigates spin transport in magnetic tunnel junctions with interfacial spin-orbit interaction, revealing how current-driven spin torque can be generated and controlled without an external polarizer, enabling magnetization switching or precession.

Contribution

It demonstrates that interfacial spin-orbit interaction alone can produce and control spin torque in magnetic tunnel junctions, a novel mechanism for spin manipulation.

Findings

Interfacial SOI induces spin torque at second order in SOI.

The torque has in-plane and perpendicular components affecting magnetization.

Bias voltage and SOI modification can control magnetization states.

Abstract

Spin transport in magnetic tunnel junctions comprising a single magnetic layer in the presence of interfacial spin-orbit interaction (SOI) is investigated theoretically. Due to the presence of interfacial SOI, a current-driven spin torque can be generated at the second order in SOI, even in the absence of an external spin polarizer. This torque possesses two components, in-plane and perpendicular to the plane of rotation, that can induce either current-driven {\em magnetization switching} from in-plane to out-of-plane configuration or {\em magnetization precessions}, similarly to Spin Transfer Torque in spin-valves. Consequently, it appears that it is possible to control the magnetization steady state and dynamics by either varying the bias voltage or electrically modifying the SOI at the interface.