Field-Free Magnetization Switching Driven by Spin-Orbit Torque in L1(0)-FeCrPt Single Layer

Electrical switching of magnetization through spin-orbit torque (SOT) induced by composition gradient in single-layer L1(0)-FePt has garnered considerable research interest owing to its inherent superior perpendicular magnetic anisotropy (PMA) that provides ultrahigh capacity to magnetic storage and memory devices. However, a large in-plane external magnetic field is typically required to assist SOT-driven switching, which is still a limitation for the practical applications of L1(0)-FePt. This study reports a realizable field-free magnetization switching by SOT via Cr doping to form a single-layer magnetic structure with an in-plane magnetization component oriented toward L1(0)-FeCrPt (110) direction that strongly depends on the magnetocrystalline anisotropy. The Cr doping yields a considerable in-plane exchange-coupling effective field that is conducive toward disintegrating the rotational switching symmetry and facilitates field-free switching in single-layer films with PMA. Furthermore, this in-plane effective field exhibits a nonmonotonic evolution with respect to the Cr-doping concentration, which is validated using first-principles calculation with a frustration-based model of magnetic exchange interactions. Thus, this study delivers an attractive method to facilitate the field-free electrical manipulations of magnetization in single-layer ferromagnets to motivate innovative designs for advanced spintronics devices.