Large enhancement of the spin Hall effect in Mn metal by Sn doping

The recent discovery of the large anomalous Hall effect (AHE) in noncollinear kagome antiferromagnets Mn3X (X=Sn, Ge) has highlighted compounds and alloys based on a combination of Mn and X. As the spin Hall effect (SHE) and AHE share the same origin, the injection of pure spin current into alloys based on Mn and X could potentially engender a large SHE. Here, we report that our spin Seebeck and the spin pumping measurements both reveal that doping Mn with 18% Sn strikingly increases the spin Hall angle of the amorphous/nanocrystalline Mn-Sn alloy by as much as 20 times while the resistivity is reduced by ten times compared with pure Mn. Our study not only serves as an essential reference for pure spin current phenomena in Mn-based alloys but may also offer a promising method for exploring future energy-saving spin Hall materials.