Giant Anomalous Hall Conductivity in a Topological Nodal‐Chain L1 ₂ ‐Fe ₃ Ga: Intrinsic and Extrinsic Origins

Nodal chain materials exhibit exceptional intrinsic anomalous transport properties due to their unique topological band structures. Here, L1 2 phase Fe 3 Ga is identified as a nodal chain metal, achieving a giant anomalous Hall conductivity (AHC) of ≈1939 S cm −1 at 10 K and 1007 S cm −1 at 300 K in polycrystalline, highlighting remarkable temperature robustness due to the significant intrinsic contribution of 1129 S cm −1 . The AHC of 1939 S cm −1 arises from a combination of intrinsic and extrinsic mechanisms, surpassing that of several prominent Weyl/nodal‐line semi‐metals, like Co 3 Sn 2 S 2 (1130 S cm −1 at 2 K). The giant intrinsic AHC originates from Berry curvature induced by a nodal chain structure, composed of two interconnected nodal rings 22 meV above the Fermi level ( E F ). The large extrinsic AHC, ≈810 S cm −1 at 10 K stems from scattering associated with minor D0 3 phase impurities. Ga doping in Fe 3‐ x Ga 1+ x triggers a Lifshitz transition at E F , shifting carrier dominance from holes to electrons, and enhances the anomalous Hall angle to 8.6% at x = 0.08 while maintaining a large intrinsic AHC. This work establishes L1 2 phase Fe 3 Ga as an ideal platform for topological studies and magnetic sensor applications based on its giant AHC.