Electrical modulation of spin-orbit torque efficiencies in electric-double-layer gated Pt/Co/Pt trilayer

Abstract

Spin current electrically generated via spin-orbit coupling exerts so-called spin-orbit torque onto ferromagnetic materials. Until now, much effort has been devoted to engineering spin-orbit torque by modifying film structure. In this method, however, spin-orbit torque could not be controlled after the device fabrication. Despite the versatile applications of spin-orbit torque in manipulating magnetic materials, the absence of dynamic tunability for spin-orbit torque has constrained the potential for constructing spin-orbit torque-based logic gates[1]. Furthermore, dynamic control of spin-orbit torque provides a novel function for the future spin-orbit torque devices. Here we focus on the electric double layer created at a polarized electrolyte/channel surface, which enables a tunable spin-charge interconversion in ultrathin Pt films through the utilization of an electric double layer[2]. In this study, we report the electrical modulation of spin-orbit torque efficiencies using electric-double-layer gating in a Pt/Co/Pt trilayer system with Ta seed layer, where the opposing spin-orbit torques from the top and bottom Pt layers cancel out each other. Harmonic Hall measurements with electric-double-layer gating reveal that the damping-like torque efficiency is switched on or off, as shown in Fig. 1. A more detailed discussion will be given in the presentation.