Room-Temperature Anomalous Inverse Spin Hall Effect in an Easy-Plane Antiferromagnetic Insulator for Néel-Vector Manipulation and Detection

Abstract

Metallic antiferromagnets are demonstrated to show an unconventional spin Hall effect (SHE) and the inverse spin Hall effect (ISHE), which are very promising for N\'eel-vector detection. However, the ISHE is absent in insulating antiferromagnets, as it does not conduct charge current. Here, we report our observation of the anomalous ISHE at the interface of the easy-plane insulator antiferromagnetic nickel oxide and the heavy metal platinum. We find that, at the interface of $\mathrm{Ni}\mathrm{O}/\mathrm{Pt}$, the ISHE generates an anomalous hysteretic transverse voltage in both Hall and planar Hall measurements, depending on spin-current propagation and the polarization direction. The observation of a nonzero transverse voltage in $\mathrm{Pt}$ indicates the appearance of a spin current with longitudinal polarization reflected from $\mathrm{Ni}\mathrm{O}$, implying N\'eel-vector reorientation from the transverse to longitudinal direction. Our simulation indicates that the N\'eel vector can be reoriented by a spin current injected from the heavy metal and an applied magnetic field. The observed anomalous ISHE permits the manipulation and detection of the N\'eel order in insulating antiferromagnets.