Effect of stoichiometry on the spin Hall angle of the half-Heusler alloy topological semimetal YPtBi

Abstract We investigated the effect of stoichiometry on the spin Hall angle of the half-Heusler alloy topological semimetal YPtBi by changing the composition ratio r of Y/Pt from 0.5 to 1.9. We confirmed that YPtBi with high C1 ordering can be deposited by co-sputtering at r = 0.5–1.5, and a large effective spin Hall angle θ SH eff of 1.7 was achieved in a junction with Pt/Co/Pt at the exact stoichiometry r = 1.0. The θ SH eff –conductivity relationship is similar to that observed in samples with exact stoichiometry, indicating that the spin Hall effect in YPtBi is robust against the change of its stoichiometry.