Chirality-Reversible Multistate Switching via Two Orthogonal Spin-Orbit Torques in a Perpendicularly Magnetized System

Abstract

Versatile spin-orbit-torque switching is potentially useful for spin logics and neuromorphic computing. Using two orthogonal spin-orbit torques, we nonvolatilely switch the magnetization of a $\mathrm{Pt}$/$\mathrm{Co}$/$\mathrm{Mg}\mathrm{O}$ crossbar with perpendicular magnetic anisotropy among multistates such as the spin-up, spin-down, and spin-random states. By electrical methods, we can even reverse the chirality of the current dependence of the magnetization from clockwise to counterclockwise. Realization of chirality-controllable switching among multistates could pave the way toward spin logics and spintronic neural computing.