Field-free switching of a Spin-orbit torque device aided by interlayer-coupling induced domain walls

TL;DR

This paper demonstrates a novel field-free switching mechanism in spin-orbit torque devices using interlayer-coupling induced domain walls, eliminating the need for an external in-plane magnetic field.

Contribution

It introduces a new device design with Tb/Co multilayers to achieve deterministic switching via domain wall movement driven by current, without external magnetic fields.

Findings

Successful field-free switching achieved through interlayer exchange coupling.

The domain wall movement is controlled by the in-plane moment direction.

Modified device with synthetic antiferromagnetic structure improves signal readout.

Abstract

The spin-orbit torque device is promising as a candidate for next generation magnetic memory, while the static in-plane field needed to induce deterministic switching is a main obstacle for its application in highly integrated circuits. Instead of introducing effective field into the device, in this work we present an alternative way to achieve the field-free current-driven magnetization switching. By adding Tb/Co multilayers at two ends of the current channel, assisting domain wall is created by interlayer exchange coupling. The field-free deterministic switching is achieved by the movement of the domain wall driven by current. By loop shift measurement we find the driven force exerted on the domain wall is determined by the direction of the in-plane moment in the domain wall. Finally, we modify the device into a synthetic antiferromagnetic structure to solve the problem of reading out signal. The present work broadens the choice of field-free spin-orbit torque device design and clearly depicts the difference between two different switching mechanism.