Spin Wave Field Effect Transistor

Spin waves (SWs) have been proposed as information carriers in novel logic devices. Voltage-controlled magnetic anisotropy (VCMA) is a promising approach to generation and control of spin waves due to its high energy efficiency. We developed a spin wave field effect transistor (SW-FET), which can turn on and turn off SW propagation in a ferromagnetic nanowire with a gate voltage via VCMA effect. We experimentally demonstrate a functioning nanoscale SW-FET based on a Ta/CoFeB/MgO multilayer nanowire. The device consists of a ferromagnetic nanowire channel magnetized out of the sample plane for SW propagation and a voltage gate on top of the wire. Propagating SWs are excited on one side of the gate via application of a localized ac spin Hall torque at the SW resonance frequency. SW propagation to the other side of the gate is detected via anomalous Hall effect (AHE). Utilizing VCMA, a dc voltage applied to the gate adjusts perpendicular magnetic anisotropy under the gate and transforms the spatially uniform magnetic energy landscape into a potential well or barrier for SW propagation depending on the gate voltage polarity. Our data demonstrate that VCMA-induced magnetic barrier can efficiently suppress SW propagation under the top gate.