Field-free spin-orbit switching of perpendicular magnetization enabled by dislocation-induced in-plane symmetry breaking
Yuhan Liang, Di Yi, Tianxiang Nan, Shengsheng Liu, Le Zhao, Yujun Zhang, Hetian Chen, Teng Xu, Minyi Dai, Jia‐Mian Hu, Ben Xu, Ji Shi, Wanjun Jiang, Rong Yu, Yuanhua Lin
Abstract
Abstract Current induced spin-orbit torque (SOT) holds great promise for next generation magnetic-memory technology. Field-free SOT switching of perpendicular magnetization requires the breaking of in-plane symmetry, which can be artificially introduced by external magnetic field, exchange coupling or device asymmetry. Recently it has been shown that the exploitation of inherent crystal symmetry offers a simple and potentially efficient route towards field-free switching. However, applying this approach to the benchmark SOT materials such as ferromagnets and heavy metals is challenging. Here, we present a strategy to break the in-plane symmetry of Pt/Co heterostructures by designing the orientation of Burgers vectors of dislocations. We show that the lattice of Pt/Co is tilted by about 1.2° when the Burgers vector has an out-of-plane component. Consequently, a tilted magnetic easy axis is induced and can be tuned from nearly in-plane to out-of-plane, enabling the field-free SOT switching of perpendicular magnetization components at room temperature with a relatively low current density (~10 11 A/m 2 ) and excellent stability (> 10 4 cycles). This strategy is expected to be applicable to engineer a wide range of symmetry-related functionalities for future electronic and magnetic devices.