Unconventional Spin‐Orbit Torques in L 1 ₀ ‐FePtRh Single Layer

ABSTRACT Electrical manipulation of magnetization switching through spin‐orbit torques (SOTs) holds considerable promise for next‐generation reliable, power‐friendly, high‐density spintronic devices. The emergence of unconventional SOTs enables fully electrical control of magnetization switching in bilayers. However, such distinctive SOTs generated by out‐of‐plane spin polarization are primarily limited to materials with low‐symmetry crystal structures or special band structures employed as spin sources in heterostructures. To date, unconventional SOTs‐driven field‐free magnetization self‐switching in single films has been rarely reported. Herein, deterministic magnetization switching driven by unconventional SOTs is demonstrated in perpendicular L 1 ₀ ‐FePtRh single films. The Rh doping introduced localized antiferromagnetic sites that are conducive to inducing out‐of‐plane effective fields, thereby facilitating field‐free self‐switching. Furthermore, at a Rh doping content of 7.5%, an effective spin Hall angle as high as 0.33 and a current‐induced magnetization switching efficiency up to 1.36 T/(10 ⁷ A cm ² ) are simultaneously obtained, exhibiting excellent comprehensive performance compared with previously reported field‐free self‐switching materials. In addition, first‐principles calculations revealed that localized antiferromagnetic exchange interaction resulting from Rh doping led to a nonzero out‐of‐plane spin current, giving rise to unconventional SOTs. These findings provide an effective strategy for realizing unconventional SOTs through atomic substitution engineering, thereby advancing the development of next‐generation spintronic devices.