Anomalous Hall effect in room-temperature two-dimensional van der Waals ferromagnets

Abstract

The anomalous Hall effect (AHE) has emerged as a powerful probe of the interplay between magnetism, electronic band topology, and spin-dependent quantum transport in two-dimensional (2D) magnetic materials. While extensive efforts have been devoted to AHE in 2D magnets, most studies have been confined to ultra-low temperatures or regimes far below room temperature, limiting both fundamental understanding and practical applicability. The recent discovery of several high-temperature van der Waals (vdW) ferromagnets has opened up a promising platform for investigating the underlying mechanisms and device opportunities of the AHE at and above room temperature. In this review, we provides a comprehensive overview of recent advancements of AHE in room-temperature 2D vdW ferromagnets. We first summarize the macroscopic manifestations of the AHE in representative vdW ferromagnets operating at room temperature. Then we provide an overview of typical vdW ferromagnetic systems exhibiting room-temperature AHE, with a particular focus on thickness dependence, Curie temperature, magnetic anisotropy, as well as material engineering strategies such as chemical doping, strain engineering, and interface design, together with state-of-the-art synthesis techniques. Subsequently, we discuss and compare the key microscopic mechanisms underlying the AHE in these materials, including intrinsic Berry-curvature-driven contributions and extrinsic contributions. Based on this understanding, recent progress in electrically tuning the AHE via external electric fields and applied currents is systematically reviewed, highlighting their impacts on anomalous Hall resistance, coercivity, and critical temperature. We further summarize advances in different types of electrically controlled vdW magnetic prototype devices, including current tunable AHE devices and magnetic tunnel junctions. Finally, we outline the significant progress achieved so far, identify the key remaining challenges, and propose promising directions for future research toward robust and functional room-temperature AHE.