Emergent zero-field anomalous Hall effect in a reconstructedrutileantiferromagnetic metal

TL;DR

This paper demonstrates the emergence of a zero-field anomalous Hall effect in Cr-doped RuO₂, a collinear antiferromagnetic metal, achieved by doping-induced reorientation of the Néel vector and magnetic moment enhancement.

Contribution

It reveals a doping strategy to induce and control zero-field AHE in collinear antiferromagnetic metals through Néel vector reorientation.

Findings

Cr doping rotates the Néel vector from [001] to [110]

Enhanced magnetic moment by an order of magnitude

AHE exhibits orientation dependence consistent with [110] Néel vector

Abstract

Anomalous Hall effect (AHE) emerged in antiferromagnetic metals shows intriguing physics and application potential. In contrast to certain noncollinear antiferromagnets, rutile RuO$_2$ has been proposed recently to exhibit a crystal-assisted AHE with collinear antiferromagnetism. However, in RuO$_2$, the on-site magnetic moment accompanying itinerant 4d electrons is quite small, and more importantly, the AHE at zero external field is prohibited by symmetry because of the high-symmetry [001] direction of the N\'eel vector. Here, we show the AHE at zero field in the collinear antiferromagnet, Cr-doped RuO$_2$. The appropriate doping of Cr at Ru sites results in a rotation of the N\'eel vector from [001] to [110] and enhancement of the on-site magnetic moment by one order of magnitude while maintaining a metallic state with the collinear antiferromagnetism. The AHE with vanishing net moment in the Ru$_{0.8}$Cr$_{0.2}$O$_2$ exhibits an orientation dependence consistent with the [110]-oriented N\'eel vector. These results open a new avenue to manipulate AHE in antiferromagnetic metals.