Magneto-ionic Control of a Propagating Spin Reorientation Transition

Mobile magnetic textures hold great potential for applications in magnetic memories and neuromorphic computing. However, energy consumption remains an issue as magnetic textures are manipulated using electrical currents. We demonstrate using magneto-ionic gating that a spin reorientation transition (SRT) between two magnetic anisotropy states can be nucleated and propagated across a magnetic track, like magnetic domain walls or skyrmions. The SRT dynamics can be controlled exclusively using gate voltage pulses down to the submillisecond range and monitored electrically via the anomalous Hall effect, with an estimated energy consumption of 64 pJ for a full switching of the device. Intermediate nonvolatile states allow for analogue operation, which could provide a synaptic potentiation/depression functionality with a significantly reduced energy cost per weight-update operation compared to current-based approaches. These results add a voltage-driven magnetic information carrier to the spintronics tool kit, offering a new avenue for the design of low-power spintronics multistate memories.