Comparison of spin Hall angles measured by spin accumulation, spin–orbit torque, and spin Hall magnetoresistance

Abstract We investigate the temperature dependence of the spin Hall angle (θ SH) in BiSb/interlayer/CoFe heterostructures using three complementary techniques: spin accumulation (SA), spin–orbit torque (SOT), and spin Hall magnetoresistance (SMR). The SA method had the largest effective spin Hall angles and the strongest temperature dependence. In contrast, the SOT and SMR methods showed smaller effective spin Hall angles and weaker temperature dependence. We attribute these differences to the different physics beyond these techniques: SOT and SMR measure the spin-transfer/spin reflection at the interlayer/FM interface and thus depend on the details of the spin transport across the interlayer and at the interlayer/FM interface. Meanwhile, SA can measure the spin Hall angle under the spin-current open circuit. Our results demonstrate that SA is a useful method for probing the intrinsic value of the spin Hall angle.