Uniform and Robust Field-Free Spin-Orbit Torque Switching via Complementary Double-Wedge Structure.

Bai, Ru; Yang, Qilin; Fan, Haodong; Feng, Zhongshu; Wei, Mingzhang; Shu, Xinyu; Han, Xiaofeng; Jin, Menghao et al. · Nano Lett · 2025

basic_science · Level V

Where this comes from

Abstract

Field-free spin-orbit torque (SOT) switching of perpendicular magnetization is crucial for next-generation magnetic storage chips. However, achieving robust, uniform, and CMOS-compatible field-free SOT switching remains a significant challenge for industrial applications. Here, a robust field-free switching scheme is proposed based on a complementary double-wedge structure with tilted magnetic anisotropy induced by the tilted Pt(111) texture, yielding a remarkable <i>z</i>/<i>y</i> effective field ratio of 89.8%. Uniform performance is obtained across 2 in. wafers for key metrics─anomalous Hall resistance, switching current density, SOT equivalent field, and field-free switching ratio. Notably, the field-free switching is maintained after annealing, confirming its compatibility with CMOS back-end-of-line processes. In addition to ensuring robust field-free switching, the complementary double-wedge design offers superior uniformity compared to the traditional single-wedge structure, making it highly suitable for mass production.