Tunable Spin and Orbital Torques in Cu-Based Magnetic Heterostructures

Abstract

Current-induced torques originating from earth-abundant 3d elements offer a promising avenue for low-cost and sustainable spintronic memory and logic applications. Recently, orbital currents─transverse orbital angular momentum flow in response to an electric field─have been in the spotlight since they allow current-induced torque generation from 3d transition metals. Here, we report a comprehensive study of the current-induced spin and orbital torques in Cu-based magnetic heterostructures. We show that high torque efficiencies can be achieved in engineered Ni₈₀Fe₂₀/Cu bilayers where Cu is naturally oxidized, exceeding the ones found in the archetypical Co/Pt. Furthermore, we demonstrate sign and amplitude control of the damping-like torque by manipulating the oxidation state of Cu via solid-state gating. Our findings provide insights into the interplay between charge, spin, and orbital transport in Cu-based heterostructures and open the door to the development of gate-tunable spin–orbitronic devices.