Anomalous Hall effect dominated by intrinsic mechanism in Fe3Ge with hexagonal DO19 Kagome lattice and cubic DO3 structure

Abstract

Intrinsic large anomalous Hall effect (AHE) due to Berry curvature (BC) has attracted much attention in recent years not only for the fundamental research but also for the potential application prospect in sensors. Iron-based alloys are one of the representative materials. In this paper, the AHE has been studied in Fe3Ge alloys with DO19 and DO3 structures. Experimental results show that both of the samples have ferromagnetic properties with spontaneous moment of 5.51 and 5.29 μB/f.u. at 5 K for DO19 and DO3 Fe3Ge, respectively. The temperature dependence of longitudinal resistivity at a zero field makes clear that DO19 and DO3 Fe3Ge have a metal behavior. The value of anomalous Hall conductivity (AHC) for DO19 and DO3 polycrystalline Fe3Ge at room temperature is 175 and 106 S/cm, respectively. It is analyzed that AHC is mainly dominated by the intrinsic scattering associated with the BC. The band structures with and without spin–orbit coupling (SOC) indicates that the nodal line will gap out at the EF due to the perturbation of SOC in DO19 Fe3Ge, which induces a large BC in the sample, leading to a great AHC. In the DO3 structure, a degenerate band along the L–G path is split, producing an enhanced BC and AHC. Stable AHC up to room temperature makes Fe3Ge a promising candidate for the device of topological spintronics.