Anisotropic Magnetoresistance and Nontrivial Spin Hall Magnetoresistance in Pt/$\alpha$-Fe$_2$O$_3$ Bilayers

TL;DR

This study reports the observation of magnetic proximity effects in Pt/α-Fe₂O₃ bilayers, revealing unique anisotropic magnetoresistance and anomalous Hall effects at low temperature, supported by a macrospin response model.

Contribution

It provides the first evidence of magnetic proximity effect in antiferromagnetic systems through ADMR measurements and introduces a macrospin model to explain the phenomena.

Findings

Observation of anomalous Hall effect and anisotropic magnetoresistance in Pt/α-Fe₂O₃ bilayers.

Evidence of magnetic proximity effect in antiferromagnetic systems.

Development of a macrospin response model explaining the ADMR features.

Abstract

To date, magnetic proximity effect (MPE) has only been conclusively observed in ferromagnet (FM) based systems. We report the observation of anomalous Hall effect and anisotropic magnetoresistance in angular dependent magnetoresistance (ADMR) measurements in Pt on antiferromagnetic (AF) $\alpha$-Fe$_2$O$_3$(0001) epitaxial films at 10 K, which provide evidence for the MPE. The N\'eel order of $\alpha$-Fe$_2$O$_3$ and the induced magnetization in Pt show a unique ADMR compared with all other FM and AF systems. A macrospin response model is established and can explain the AF spin configuration and all main ADMR features in the Pt/$\alpha$-Fe$_2$O$_3$ bilayers.