Magnetic-field and temperature dependence of anomalous Hall effect in Pt/Cr2O3/Pt trilayer

Xinrui Wang,Yu Shiratsuchi,Kentaro Toyoki,Ryoichi Nakatani

doi:10.1063/9.0000253

Abstract

The Pt/Cr2O3 interface exhibits a variety of spin-related phenomena. In this study, we investigated the anomalous Hall effect (AHE) of a Pt/40-nm-thick Cr2O3/Pt trilayer grown on Al2O3(0001), where Cr2O3 is an antiferromagnetic (AFM) insulator. All layers were grown epitaxially on the substrate, and X-ray reflectivity measurement showed an interfacial roughness of approximately 0.2 nm at each interface. The AHE resistance showed a nonlinear magnetic-field dependence at 300 K. Below 250 K, a clear hysteresis with coercivity was observed. The coercivity was approximately 7 T above 150 K and approximately 6 T below 100 K. The remanent AHE resistance shows a finite value below 285 K. The temperature dependence forms a broad peak with a maximum at approximately 200 K and gradually decreases with decreasing temperature. This temperature dependence is similar to that reported for the interfacial magnetic moment on Cr2O3(0001). Based on these results, the remanent AHE coupled with the AFM order parameter or the Néel vector was successfully detected in the 40-nm-thick Cr2O3 layer grown on the conductive layer.

Highlights

Antiferromagnetic (AFM) spintronics has been an area of active research.1 The absence of net magnetization makes antiferromagnets robust against perturbations by an external magnetic field
The detection of the AFM order parameter of Cr2O3 based on transport measurements was first proposed by Kosub et al.6 using the Pt/Cr2O3 bilayer, where the remanent anomalous Hall effect (AHE) resistance was assumed to be an imprint of the AFM order parameter
The 40-nm-thick Cr2O3 layer grown on the Pt(111) buffer layer showed a high electrical resistivity of approximately 1 × 106 Ωcm

Summary

INTRODUCTION

Antiferromagnetic (AFM) spintronics has been an area of active research. The absence of net magnetization makes antiferromagnets robust against perturbations by an external magnetic field. For the detection of AFM moment/domains, previous studies have used spin-related transport phenomena such as the anomalous Hall effect (AHE) and planar Hall effect, optical techniques, and synchrotron measurements based on magnetic linear/circular dichroism.. The detection of the AFM order parameter of Cr2O3 based on transport measurements was first proposed by Kosub et al. using the Pt/Cr2O3 bilayer, where the remanent AHE resistance was assumed to be an imprint of the AFM order parameter. This technique has been extended to the detection of the ME-controlled AFM order parameter.. In addition to the reduction of Cr2O3 thickness, our investigations cover a high magnetic field above 6 T and a wide temperature range of 10–310 K, in contrast to previous reports where the applied magnetic field strength is typically below 3 T18 and the temperature regime is typically above 250 K.3,5,18

EXPERIMENTAL

SUMMARY