Sign Change of Spin-Orbit Torque in Pt/NiO/CoFeB Structures

Antiferromagnetic insulators have recently been proved to support spin current efficiently. Here, we report the dampinglike spin-orbit torque (SOT) in Pt/NiO/CoFeB has a strong temperature dependence and reverses the sign below certain temperatures, which is different from the slight variation with temperature in the Pt/CoFeB bilayer. The negative dampinglike SOT at low temperatures is proposed to be mediated by the magnetic interactions that tie with the ???exchange bias??? in Pt/NiO/CoFeB, in contrast to the thermal-magnon-mediated scenario at high temperatures. Our results highlight the promise to control the SOT through tuning the magnetic structure in multilayers.

Automated summary

Recent studies have shown that antiferromagnetic insulators efficiently support spin current. In this study, we observe a strong temperature dependence and reversed sign of dampinglike spin-orbit torque (SOT) in Pt/NiO/CoFeB, which is different from the slight variation with temperature observed in Pt/CoFeB bilayer. The negative dampinglike SOT at low temperatures is proposed to be mediated by magnetic interactions tied to the "exchange bias" in Pt/NiO/CoFeB, in contrast to the thermal-magnon-mediated scenario at high temperatures. These results highlight the potential to control SOT by tuning the magnetic structure in multilayers.