Angle dependent hysteretic magnetotransport in MnBi2Te4 nanoflakes

TL;DR

This study investigates the angle-dependent hysteretic magnetotransport in MnBi2Te4 nanoflakes, revealing thickness-dependent magnetic irreversibility influenced by domain wall dynamics, highlighting the role of reduced dimensionality.

Contribution

It provides the first detailed analysis of hysteretic magnetoresistance in nanoscale MnBi2Te4, emphasizing the impact of thickness and angular anisotropy on magnetic irreversibility.

Findings

Hysteretic magnetoresistance varies non-monotonically with thickness.

Angular anisotropy indicates complex magnetic behavior.

Magnetic irreversibility likely involves domain wall pinning.

Abstract

Controlling magnetic phases in two-dimensional systems, where charge transport is highly sensitive to real-space spin inhomogeneities, is central to understanding emergent magnetic states in reduced dimensions. In this context, thickness-dependent magnetotransport provides access to irreversible magnetic processes that are not captured by reversible transport or bulk magnetization alone. Here we report an extensive study of hysteretic magnetoresistance in single-crystalline nanoscale thin flakes of the layered antiferromagnet MnBi2Te4. The multi-step hysteresis exhibits a pronounced non-monotonic dependence on thickness and displays nontrivial angular anisotropy. The transport signatures rule out surface-dominated magnetism and simple bulk metamagnetic transitions as the primary origin. We argue that the magnetic irreversibility is possibly governed by domain wall pinning and de-pinning processes within a spatially non-uniform magnetic landscape. These results suggest that reduced dimensionality is a key driver of magnetic irreversibility in MnBi2Te4.