Magnetization Switching of a Thin Ferromagnetic Layer by Spin-Orbit Torques

We conducted micromagnetic simulations to investigate magnetization switching dynamics in ferromagnet/nonmagnet bilayers driven by an in-plane current for 1) free layer with out-of-plane anisotropy, 2) free layer with in-plane anisotropy, and 3) free layer with both in-plane anisotropy and electric-field-controlled out-of-plane anisotropy. The effects of various material parameters on the switching performance are discussed. Based on the simulations, a fast and reliable switching scheme may be realized by using in-plane magnetization switching assisted by an electric-field-controlled out-of-plane magnetic anisotropy. This fast and deterministic switching does not require any external magnetic fields.