Zhou Jing, Shu Xinyu, Lin Weinan, Shao Ding Fu, Chen Shaohai, Liu Liang, Yang Ping, Tsymbal Evgeny Y, Chen Jingsheng
Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore, 117575, Singapore.
Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE, 68588, USA.
Adv Mater. 2021 Jul;33(30):e2007114. doi: 10.1002/adma.202007114. Epub 2021 Jun 19.
Spin-orbit torque (SOT), which arises from the spin-orbit coupling of conduction electrons, is believed to be the key route for developing low-power, high-speed, and nonvolatile memory devices. Despite the theoretical prediction of pronounced Berry phase curvatures in certain transition-metal perovskite oxides, which lead to considerable intrinsic spin Hall conductivity, SOT from this class of materials has rarely been reported until recently. Here, the SOT generated by epitaxial SrRuO of three different crystal structures is systematically studied. The results of both spin-torque ferromagnetic resonance and in-plane harmonic Hall voltage measurements concurrently reveal that the intrinsic SOT efficiency of SrRuO decreases when the epitaxial strain changes from tensile to compressive. The X-ray diffraction data demonstrate a strong correlation between the magnitude of SOT and octahedral rotation around the in-plane axes of SrRuO , consistent with the theoretical prediction. This work offers new possibilities of tuning SOT with crystal structures and novel opportunities of integrating the unique properties of perovskite oxides with spintronic functionalities.
自旋轨道扭矩（SOT）源于传导电子的自旋轨道耦合，被认为是开发低功耗、高速和非易失性存储器件的关键途径。尽管理论预测某些过渡金属钙钛矿氧化物中存在明显的贝里相曲率，这会导致可观的本征自旋霍尔电导率，但直到最近，这类材料产生的SOT鲜有报道。在此，系统研究了三种不同晶体结构的外延SrRuO所产生的SOT。自旋扭矩铁磁共振和面内谐波霍尔电压测量结果同时表明，当外延应变从拉伸变为压缩时，SrRuO的本征SOT效率会降低。X射线衍射数据表明，SOT的大小与SrRuO面内轴周围的八面体旋转之间存在很强的相关性，这与理论预测一致。这项工作为通过晶体结构调节SOT提供了新的可能性，并为将钙钛矿氧化物的独特性质与自旋电子功能集成提供了新的机遇。
