Dynamics of domain wall induced by voltage-controlled strain-field gradient

Abstract

This work investigates the strain-gradient-driven domain wall (DW) motion in a ferromagnetic-heavy-metal–piezoelectric heterostructure with perpendicular magnetic anisotropy and the interface Dzyaloshinskii-Moriya interaction (iDMI). The simulation results show that a larger iDMI can lead to greater tilting of the DW surface as the DW approaches the end of the wire. When the DW stops, the tilt angle is zero, and the DW is perpendicular to the nanowire. The DW displacement and the velocity are affected by the iDMI coefficient, strain-gradient amplitude, and Gilbert damping. We also show that such a mechanism can be used to implement a leaky-integrate-fire spiking neuron device with the controllable temporary location of the DW serving as the analog membrane potential of a biological neuron, which is promising for future DW-based artificial neural devices.