Competing magnetic states in a non-coplanar Kagome magnet

TL;DR

This paper reports the discovery of an intrinsic non-coplanar spin state in Mn3Ge that persists up to 400 K, leading to unconventional anomalous Hall effects and advancing the understanding of non-coplanar magnetism in antiferromagnetic spintronics.

Contribution

It reveals a stable non-coplanar magnetic state in Mn3Ge at high temperatures, driven by competing exchange interactions, and demonstrates its impact on anomalous Hall effects.

Findings

Non-coplanar spin configuration persists up to 400 K.

Unconventional anomalous Hall effect with sign reversal.

Competing exchange interactions induce non-coplanar magnetism.

Abstract

Non-collinear Kagome antiferromagnets (AFMs) Mn3X (X = Sn, Ga, Ge, Ir, Pt) can generate an anomalous Hall effect (AHE) despite vanishing net magnetization, enabled by broken time-reversal and inversion symmetries. However, strong in-plane anisotropy has limited studies of the AFM-AHE and electronic applications to coplanar spin configurations. Non-coplanar spin textures in these systems have been realized only in low temperature spin-glass states or at interfaces with heavy metals. Here, we report an intrinsic non-coplanar spin configuration persisting up to 400 K in cubic-phase Mn3Ge, originating from coexisting symmetric and antisymmetric exchange interactions. Competing magnetic states associated with this non-coplanar spin configuration give rise to an unconventional AHE with a magnetic-field-induced sign reversal and a hump-like feature. Our findings establish a platform for non-coplanar magnetism in AFM spintronics.