In-situ monitoring the magnetotransport signature of topological transitions in the chiral magnet Mn$_{1.4}$PtSn

TL;DR

This study introduces a high-resolution in-situ measurement platform combining Lorentz transmission electron microscopy and Hall voltage measurement to directly correlate magnetic textures with Hall effects in Mn$_{1.4}$PtSn, clarifying the origins of observed Hall signals.

Contribution

It presents a novel in-situ approach to directly link magnetic textures with Hall effect signatures, enabling clear distinction between topological and anomalous Hall effects.

Findings

Magnetic textures in Mn$_{1.4}$PtSn do not produce a topological Hall effect.

Field-controlled formation and annihilation of antiskyrmions do not affect the Hall voltage.

The observed Hall signals can be explained without invoking topological contributions.

Abstract

Emerging magnetic fields related to the presence of topologically protected spin textures such as skyrmions are expected to give rise to additional, topology-related contributions to the Hall effect. In order to doubtlessly identify this so-called topological Hall effect, it is crucial to disentangle such contributions from the anomalous Hall effect. This necessitates a direct correlation of the transversal Hall voltage with the underlying magnetic textures. We utilize a novel measurement platform that allows to acquire high-resolution Lorentz transmission electron microscopy images of magnetic textures as a function of an external magnetic field and to concurrently measure the (anomalous) Hall voltage in-situ in the microscope on one and the same specimen. We use this approach to investigate the transport signatures of the chiral soliton lattice and antiskyrmions in Mn$_{1.4}$PtSn. Notably, the observed textures allow to fully understand the measured Hall voltage without the need of any additional contributions due to a topological Hall effect, and the field-controlled formation and annihilation of anstiskyrmions are found to have no effect on the measurend Hall voltage.