Spin–orbit torque induced magnetization switching for an ultrathin MnGa/Co2MnSi bilayer

Kohey Jono,Michihiko Yamanouchi,Tetsuya Uemura,Fumiaki Shimohashi

doi:10.1063/5.0032732

Abstract

We investigated spin–orbit torque (SOT) induced magnetization switching and SOT efficiency for Mn1.8Ga1.0 (MnGa) single layers and MnGa/Co2MnSi (CMS) bilayers. Magnetization measurements showed that ultrathin MnGa and CMS were antiferromagnetically coupled to each other with clear perpendicular magnetization. SOT-induced magnetization switching was observed for both MnGa/CMS/Ta and MnGa/Ta stacks, and the switching current was reduced by a half in the MnGa/CMS/Ta stack. Examination of SOT acting on the domain walls revealed that the effective magnetic field originating from the SOT was approximately five times stronger in the MnGa/CMS/Ta stack than in the MnGa/Ta stack. These results indicate that the MnGa/CMS bilayer structure is effective in enhancing the efficiency of SOT generation.

Highlights

Cobalt-based Heusler alloys (Co2YZ, where Y is usually a transition metal and Z is a main group element) are candidates for such an insertion layer because of the half-metallic nature theoretically predicted for many of these alloys
Previous studies have demonstrated that MnGa and CMS are antiferromagnetically coupled to each other,34,35 and a perpendicular magnetic tunnel junctions (p-MTJs) with MnGa/CMS electrodes has been reported
The effective magnetic field originating from the spin–orbit torque (SOT) in the MnGa[3]/CMS/Ta and MnGa[3]/Ta devices was evaluated by examining the SOT acting on the domain walls (DWs)

Summary

Introduction

Cobalt-based Heusler alloys (Co2YZ, where Y is usually a transition metal and Z is a main group element) are candidates for such an insertion layer because of the half-metallic nature theoretically predicted for many of these alloys. This antiferromagnetic coupling of MnGa and CMS is consistent with the findings in previous studies.34,35 it is supported by the results of anomalous Hall effect measurements scitation.org/journal/adv shown later.

Objectives

Results

Conclusion