Giant anisotropic anomalous Hall effect in antiferromagnetic topological metal NdGaSi

The interplay between magnetism and strong electron correlation in magnetic materials discerns a variety of intriguing topological features. Here, we report a systematic investigation of the magnetic, thermodynamic, and electrical transport properties in NdGaSi single crystals. The magnetic measurements reveal a magnetic ordering below T_N (11 K), with spins aligning antiferromagnetically in-plane, and it orders ferromagnetically (FM) out-of-plane. The longitudinal resistivity data and heat capacity exhibit a significant anomaly as a consequence of the magnetic ordering at TN. The magnetoresistance study shows significantly different behavior when measured along either direction, resulting from the complex nature of the magnetic structure, stemming from complete saturation of moments in one direction and subsequent spin flop transitions in the other. Remarkably, we have also noticed an unusual anisotropic anomalous Hall response. We have observed a giant anomalous Hall conductivity (AHC) of 1730 ohm-1 cm-1 and 490 ohm-1 cm-1 at 2 K, with B // [001] and B // [100], respectively. Our scaling analysis of AHC reveals that the anomalous Hall effect in the studied compound is dominated by the Berry phase-driven intrinsic mechanism. These astonishing findings in NdGaSi open up new possibilities for antiferromagnetic spintronics in rare-earth-based intermetallic compounds.