Field-Free Magnetization Switching Driven by Spin–Orbit Torque in L1_0-FeCrPt Single Layer

摘要

Electrical switching of magnetization through spin–orbit torque (SOT)induced by a composition gradient in single-layer L1_0-FePt has garneredconsiderable research interest owing to its inherent superior perpendicularmagnetic anisotropy (PMA) that provides ultrahigh capacity to magneticstorage and memory devices. However, a large in-plane external magneticfield is typically required to assist SOT-driven switching, which is still a limitationfor the practical application of L1_0-FePt. This study reports realizablefield-free magnetization switching by SOT via Cr doping to form a singlelayermagnetic structure with an in-plane magnetization component orientedtoward L1_0-FeCrPt 11_0 direction that strongly depends on the magnetocrystallineanisotropy. The Cr doping yields a considerable in-plane exchangecouplingeffective field that is conducive toward disintegrating the rotationalswitching symmetry and facilitates field-free switching in single-layer filmswith PMA. Furthermore, this in-plane effective field exhibits a nonmonotonicevolution with respect to the Cr-doping concentration, which is validatedusing first-principles calculation with a frustration-based model of magneticexchange interactions. Thus, this study delivers an attractive method tofacilitate the field-free electrical manipulations of magnetization in singlelayerferromagnets to motivate innovative designs for advanced spintronicsdevices.