Observation of an Anomalous Hall Effect in Single-crystal Mn3Pt

TL;DR

This study demonstrates the first observation of a significant anomalous Hall effect in a bulk single-crystal of cubic Mn3Pt, using stress and magnetic fields to align antiferromagnetic domains, confirming the effect's intrinsic nature.

Contribution

It is the first to observe a substantial AHE in a cubic Mn3X compound, expanding understanding of antiferromagnetic materials with Berry curvature effects.

Findings

AHE observed in bulk Mn3Pt with stress and magnetic field

AHE remains stable after stress removal, indicating intrinsic origin

Demonstrates domain alignment techniques for cubic antiferromagnets

Abstract

The Mn3X family of compounds was the first in which a large anomalous Hall effect (AHE) was predicted to arise from a purely antiferromagnetic structure, due to the Berry curvature in momentum space. Nearly simultaneously with this prediction, a large AHE was observed experimentally in one of the hexagonal members of this family, Mn3Sn. Aligning antiferromagnetic domains, a necessary step for observation of the AHE, is more challenging for the cubic members of the Mn3X family, due to a combination of a smaller spontaneous ferromagnetic moment and much stronger magnetic anisotropy. Here, we use a combination of uniaxial stress and applied magnetic field to align domains of bulk single-crystal Mn3Pt, and demonstrate for the first time a substantial AHE in a bulk sample of a cubic member of the Mn3X family. The AHE remains locked in with essentially no quantitative variation when the stress is ramped back to zero, which shows that it is not a consequence of any stress-induced ferromagnetic moment.