Sign Change of Spin-Orbit Torque in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>Pt</mml:mi><mml:mo>/</mml:mo><mml:mi>NiO</mml:mi><mml:mo>/</mml:mo><mml:mi>CoFeB</mml:mi></mml:mrow></mml:math> Structures
Dapeng Zhu, Tianrui Zhang, Xiao Fu, Runrun Hao, A. Hamzić, Huaiwen Yang, Xueying Zhang, Hui Zhang, Ao Du, Danrong Xiong, Kewen Shi, Shishen Yan, Shufeng Zhang, A. Fert, Weisheng Zhao
Abstract
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.