Anomalous Hall effect in Pt/Al-doped Cr2O3 epitaxial film

Abstract

The anomalous Hall effect (AHE) was studied for the Pt(111)/(Al0.04Cr0.96)2O3(0001) epitaxial bilayer wherein the finite small magnetization is intentionally generated by doping Al in the pure antiferromagnetic Cr2O3. Despite that the (Al0.04Cr0.96)2O3 layer is an insulator, the sizable AHE accompanied with the hysteresis against the magnetic field reversal was obtained. The hysteresis is attributed to the magnetization reversal of the (Al0.04Cr0.96)2O3 layer. The anomalous Hall conductivity shows two characteristics in the temperature dependence: the turndown with decreasing temperature and the dip near the Néel temperature. These are distinct from the temperature dependence of the magnetization showing the monotonic decrease with increasing temperature. The discussion yields a plausible mechanism of the AHE as spin-chiral texture in the momentum space as the theory predicted for the Pt/Cr2O3 interface.