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

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.