Investigating the origin of topological-Hall-like resistivity in Zn-doped Mn2Sb ferrimagnet

TL;DR

This study investigates Hall-resistivity anomalies in Zn-doped Mn2Sb ferrimagnet, revealing they are due to trivial mechanisms rather than chiral spin textures, challenging previous interpretations of topological Hall effects.

Contribution

The paper demonstrates that Hall-resistivity anomalies in this ferrimagnet are caused by sample inhomogeneity, not chiral spin textures, emphasizing the need for careful interpretation of topological Hall signals.

Findings

Hall-resistivity anomalies are uncorrelated with magnetic transitions.

Lorentz TEM shows no evidence of chiral spin textures.

Anomalies are due to multiple anomalous Hall channels from inhomogeneity.

Abstract

Skyrmions and other chiral spin textures have been extensively studied as potential building blocks for novel spintronic devices. Hall-resistivity anomalies that deviate from magnetization scaling, known as the topological Hall effect, have been widely employed as evidence for the presence of chiral spin textures in magnetic materials. However, recent studies on magnetic thin films have revealed a drawback of this approach, as the presumed topological Hall contribution may in fact originate from trivial mechanisms. Here, we investigate the magnetic and transport properties of a Zn-doped Mn2Sb ferrimagnet, whose related compounds have previously been suggested to exhibit a topological Hall effect arising from chiral spin textures. Hall-resistivity anomalies are also observed in our sample, yet they show little correlation with the magnetic or metamagnetic transitions and are therefore clearly distinct from those in magnetic compounds hosting chiral spin textures. Most importantly, additional Lorentz transmission electron microscopy measurements rule out the existence of chiral spin textures in this ferrimagnet. Therefore, instead of a nontrivial origin, we attribute the Hall-resistivity anomalies to the combined effect of multiple anomalous Hall channels resulting from sample inhomogeneity. Our work shows that the difficulties of identifying chiral spin textures through transport measurements also apply to bulk systems, prompting some existing results to be revisited.