Perpendicular magnetization reversal in Pt/[Co/Ni]$_3$/Al multilayers via the Spin Hall Effect of Pt

TL;DR

This study demonstrates current-induced magnetization reversal in multilayers driven by the Spin Hall Effect of Pt, with control over domain nucleation and propagation using magnetic fields and spin torques.

Contribution

It provides experimental evidence of controlling magnetization reversal via spin Hall effect and domain wall manipulation in multilayer structures.

Findings

Magnetization reversal occurs at ~0.3 TA/m$^2$ current density.

Domain nucleation controlled by Oersted field.

Domain-wall propagation driven by spin torque from Pt's Spin Hall Effect.

Abstract

We experimentally investigate the current-induced magnetization reversal in Pt/[Co/Ni]$_3$/Al multilayers combining the anomalous Hall effect and magneto-optical Kerr effect techniques in crossbar geometry. The magnetization reversal occurs through nucleation and propagation of a domain of opposite polarity for a current density of the order of 0.3 TA/m$^2$. In these experiments we demonstrate a full control of each stage: i)the {\O}rsted field controls the domain nucleation and ii) domain-wall propagation occurs by spin torque from the Pt spin Hall effect. This scenario requires an in-plane magnetic field to tune the domain wall center orientation along the current for efficient domain wall propagation. Indeed, as nucleated, domain walls are chiral and N\'eel like due to the interfacial Dzyaloshinskii-Moriya interaction.