Global Satellite Session - Hong Kong: Soft Matter and Quantum Systems

The Anomalous Hall Effect (AHE) is a crucial spin-dependent transport phenomenon, providing insights into the interplay between electronic structure and magnetic properties of materials. Achieving high anomalous Hall conductivity (AHC) is particularly important, as it enables the exploration of extrinsic mechanisms, which dominate in the high conductivity regime. Despite its significance, this regime remains largely unexplored. We investigated the AHE in high-quality epitaxial Fe films on MgAl2O4 (001) substrates, achieving longitudinal conductivities up to 107 S/cm. The Hall conductivity exceeds 106 S/cm, a three-order-of magnitude enhancement over Fe’s intrinsic AHC, with an anomalous Hall angle of 10%, comparable to topological semimetals and Heusler compounds. At low temperatures and varying thicknesses, the Hall conductivity scales quadratically with longitudinal conductivity, deviating from conventional linear scaling. The thick Fe films exhibit an increasement of the anomalous Hall resistivity below 100 K, attributed to the enhanced skew scattering induced by the thickness-confinement effect. These findings reveal a previously unrecognized role of confinement in tailoring spin-dependent transport and offer a robust strategy for amplifying the AHE in conventional magnetic materials. By extending the exploration of AHE into the high-conductivity regime, this work establishes a new paradigm for understanding and engineering spin-dependent transport phenomena. These insights have broad implications, opening avenues for next-generation spintronic devices and advancing the design of magnetic materials with exceptional transport properties.