Manipulation of Spin–Orbit Torque in Tungsten Oxide/Manganite Heterostructure by Ionic Liquid Gating and Orbit Engineering

Spin–orbit coupling (SOC) is the interaction between electron’s spin and orbital motion, which could realize a charge-to-spin current conversion and enable an innovative method to switch the magnetization by spin–orbit torque (SOT). Varied techniques have been developed to manipulate and improve the SOT, but the role of the orbit degree of freedom, which should have a crucial bearing on the SOC and SOT, is still confusing. Here, we find that the charge-to-spin current conversion and SOT in W 3 O 8−δ /(La, Sr)MnO 3 could be produced or eliminated by ionic liquid gating. Through tuning the preferential occupancy of Mn/W- d electrons from the in-plane ( d x 2 – y 2 ) to out-of-plane ( d 3 z 2 – r 2 ) orbit, the SOT damping-like field efficiency is nearly doubled due to the enhanced spin Hall effect and interfacial Rashba-Edelstein effect. These findings not only offer intriguing opportunities to control the SOT for high-efficient spintronic devices but also could be a fundamental step toward spin–orbitronics in the future.