Spin-orbit torque in Pt/CoNiCo/Pt symmetric devices

TL;DR

This paper investigates spin-orbit torques in symmetric Pt/CoNiCo/Pt devices, demonstrating a dominant damping-like torque from the spin Hall effect and negligible field-like torque, with implications for energy-efficient magnetic switching.

Contribution

It provides a quantitative analysis of spin Hall and Rashba effects in symmetric structures, highlighting the dominance of damping-like torque in magnetization switching.

Findings

Strong damping-like torque from spin Hall effect

Unmeasurable field-like torque from Rashba effect

Non-linear switching behavior explained by micromagnetic simulation

Abstract

Current induced magnetization switching by spin-orbit torques offers an energy-efficient means of writing information in heavy metal/ferromagnet (FM) multilayer systems. The relative contributions of field-like torques and damping-like torques to the magnetization switching induced by the electrical current are still under debate. Here, we describe a device based on a symmetric Pt/FM/Pt structure, in which we demonstrate a strong damping-like torque from the spin Hall effect and unmeasurable field-like torque from Rashba effect. The spin-orbit effective fields due to the spin Hall effect were investigated quantitatively and were found to be consistent with the switching effective fields after accounting for the switching current reduction due to thermal fluctuations from the current pulse. A non-linear dependence of deterministic switching of average Mz on the in-plane magnetic field was revealed, which could be explained and understood by micromagnetic simulation.