Electrical Control of Spin Hall Efficiency and Field-Free Magnetization Switching in W/Pt/Co/Pt Heterostructures with Competing Spin Currents.

Reversal of magnetization via current-induced spin-orbit torque (SOT) is one of the core issues in spintronics. However, an in-plane assistant field is usually required for the deterministic switching of a perpendicularly magnetized system. Additionally, the efficiency of SOT is low, which is detrimental to device applications. This study achieved a reversible and non-volatile control of the critical current for magnetization switching and spin Hall efficiency in the TaN/W/Pt/Co/Pt/TaN heterostructures by ionic liquid (IL) gating-induced hydrogen ion adsorption and desorption in the upper Pt layer. Furthermore, the thinning of the Pt and TaN capping layers activated the oxygen ion migration toward the Co layer under IL gating, resulting in an exchange bias field and allowing field-free magnetization switching and Boolean logic operation. The results of this study offer an intriguing opportunity to promote the development of SOT-based spintronic devices from the perspective of iontronics with low energy dissipation.