Unveiling the Anomalous Hall Response of the Magnetic Structure Changes in the Epitaxial MnBi₂Te₄ Films

Recently discovered as an intrinsic antiferromagnetic topological insulator, MnBi₂Te₄ has attracted tremendous research interest, as it provides an ideal platform to explore the interplay between topological and magnetic orders. MnBi₂Te₄ displays distinct exotic topological phases that are inextricably linked to the different magnetic structures of the material. In this study, we conducted electrical transport measurements and systematically investigated the anomalous Hall response of epitaxial MnBi₂Te₄ films when subjected to an external magnetic field sweep, revealing the different magnetic structures stemming from the interplay of applied fields and the material's intrinsic antiferromagnetic (AFM) ordering. Our results demonstrate that the nonsquare anomalous Hall loop is a consequence of the distinct reversal processes within individual septuple layers. These findings shed light on the intricate magnetic structures in MnBi₂Te₄ and related materials, offering insights into understanding their transport properties and facilitating the implementation of AFM topological electronics.