Strain-mediated spin-orbit torque enhancement in Pt/Co on flexible substrate

• Main Authors: Wong, Grayson Dao Hwee, Xu, Zhan, Gan, Weiliang, Ang, Calvin Ching Ian, Law, Wai Cheung, Tang, Jiaxuan, Zhang, Wen, Wong, Ping Kwan Johnny, Yu, Xiaojiang, Xu, Feng, Wee, Andrew T. S., Seet, Chim Seng, Lew, Wen Siang
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2022
• Subjects: Science::Physics; Spin Hall Effect; Spin−Orbit Torque; Ferromagnetic Resonance
• Online Access: https://hdl.handle.net/10356/160133
• Institution: Nanyang Technological University

Current-induced magnetization switching by spin-orbit torque generated in heavy metals offers an enticing realm for energy-efficient memory and logic devices. The spin Hall efficiency is a key parameter in describing the generation of spin current. Recent findings have reported enhancement of spin Hall efficiency by mechanical strain, but its origin remains elusive. Here, we demonstrate a 45% increase in spin Hall efficiency in the platinum/cobalt (Pt/Co) bilayer, of which 78% of the enhancement was preserved even after the strain was removed. Spin transparency and X-ray magnetic circular dichroism revealed that the enhancement was attributed to a bulk effect in the Pt layer. This was further confirmed by the linear relationship between the spin Hall efficiency and resistivity, which indicates an increase in skew-scattering. These findings shed light on the origin of enhancement and are promising in shaping future utilization of mechanical strain for energy-efficient devices.