Sign reversal of magnetoresistance and anisotropic anomalous Hall conductivity in the Fe-doped Mn5Ge3 single crystal

Magnetic Weyl materials have attracted extensive research attention due to their unique topological properties, in particular anomalous magneto-transport responses. Here, we report the discovery of an obvious sign reversal of magnetoresistance (MR) in the Fe-doped magnetic Weyl nodal ring semimetal Mn4FeGe3 single crystal, which exhibits an enhanced Curie temperature of 325 K and an easy magnetization axis within the ab-plane. Moreover, we found that the anomalous Hall conductivity (AHC) of Mn4FeGe3 shows pronounced anisotropic behavior and its value strongly depends on the relative orientation between the current and the magnetic field. Our results emphasize that the charge current direction acts as a strategy to tune the AHC in Mn4FeGe3: the intrinsic Berry curvature mechanism dominates for ab-plane transport, whereas the extrinsic skew scattering prevails when the current flows along the c axis. This work suggests Mn4FeGe3 as a promising platform for tuning both the MR and the anomalous Hall responses, which will be useful for various applications, including spintronics.