Field-free spin–orbit torque-induced magnetization switching in a miscut-substrate driven slant-perpendicular magnetic anisotropy system

Abstract

In a perpendicular magnetic anisotropy (PMA) system, spin–orbit torque (SOT)-induced magnetization switching shows promise in terms of high speed and stability, but additional in-plane directional symmetry breaking is necessary to achieve deterministic switching. Here, we observed all-electric magnetization switching by SOT in a conventional heavy metal/ferromagnetic structure deposited on a 3.25° miscut sapphire substrate. To better understand the origin of field-free switching, we conducted azimuthal angle-dependent PMA analysis and found that the magnetic anisotropy is slightly tilted in the direction of the miscut step. Despite a few degrees of tilting angle (<3°), we also confirmed that a slant PMA is the origin of the field-free switching by micromagnetic simulations.