Tuning of Anomalous Hall Effect by Systematic Doping on Mn3Sn

Mn3Sn is an AHE antiferromagnet exhibiting a hysteretic anomalous Hall effect (AHE) originating from the cluster octupole moments of inverse triangular antiferromagnetic spins at room temperature, whereas the AHE disappears at low temperatures. In this study, we evaluated the systematic doping effect on the AHE of Mn3Sn to stabilize the AHE at low temperatures. We grew single crystals of M0.1Mn2.9Sn and Mn3Sn0.9X0.1 (M = Cr and Fe; X = Si and Ge) and evaluated their transport and magnetic properties. Compared with doping at the Sn site, doping at the Mn site drastically changes the AHE at low temperatures. Reproducible magnetic structures were not observed at low temperatures owing to low Fe content fluctuation near x similar to 0.1 in FexMn3-xSn. Some crystals showed a large hysteretic-type AHE, unlike the AHE at 300 K, while others did not show a finite AHE below 50 K. Conversely, Cr doping stabilizes the AHE with additional magnetoresistance that hinders observing the AHE. Considering these features, we prepared Cr and Fe codoped Mn3Sn crystals. The Fe-0.05/Cr-0.1-doped Mn3Sn crystals showed the AHE from room temperature to 2 K without magnetic transitions. This finding provides a new route to access octupole-driven phenomena of Mn3Sn-based devices at low temperatures.