Unusual Anomalous Hall Effect in Two-Dimensional Ferromagnetic Cr₇Te₈

Two-dimensional (2D) materials with inherent magnetism have attracted considerable attention in the fields of spintronics and condensed matter physics. The anomalous Hall effect (AHE) offers a theoretical foundation for understanding the origins of 2D ferromagnetism (2D-FM) and offers a valuable opportunity for applications in topological electronics. Here, we present uniform and large-size 2D Cr₇Te₈ nanosheets with varying thicknesses grown using the chemical vapor deposition (CVD) method. The 2D Cr₇Te₈ nanosheets with robust perpendicular magnetic anisotropy, even a few layers deep, exhibit a Curie temperature (T_C) ranging from 180 to 270 K according to the varying thickness of Cr₇Te₈. Moreover, we observed a temperature-induced reversal in the sign of the anomalous Hall resistance, correlating with changes in the intrinsic Berry curvature. Additionally, the topological Hall effect (THE) observed at low temperatures suggests the presence of non-trivial spin chirality. Our findings about topologically non-trivial magnetic spin states in 2D ferromagnets provide a promising opportunity for new designs in magnetic memory spintronics.