Angle dependent hysteretic magnetotransport in MnBi2Te4 nanoflakes
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.