# Electric-field-driven domain wall dynamics in perpendicularly magnetized multilayers

## TL;DR

This study demonstrates reversible electric-field control of magnetic domain wall motion in a multilayer heterostructure via strain coupling with a ferroelectric substrate, revealing velocity dependence on electric field strength and independence from magnetic fields.

## Contribution

It introduces a method for electric-field-driven magnetic domain wall manipulation in multilayers using strain coupling with ferroelectric BaTiO$_3$, showing controllable and reversible domain wall motion.

## Key findings

- Electric field pulses move magnetic and ferroelectric domain walls in unison.
- Domain wall velocity increases exponentially with electric field strength.
- Magnetic fields do not influence domain wall velocity but modify internal spin structure.

## Abstract

We report on reversible electric-field-driven magnetic domain wall motion in a Cu/Ni multilayer on a ferroelectric BaTiO$_3$ substrate. In our heterostructure, strain-coupling to ferroelastic domains with in-plane and perpendicular polarization in the BaTiO$_3$ substrate causes the formation of domains with perpendicular and in-plane magnetic anisotropy, respectively, in the Cu/Ni multilayer. Walls that separate magnetic domains are elastically pinned onto ferroelectric domain walls. Using magneto-optical Kerr effect microscopy, we demonstrate that out-of-plane electric field pulses across the BaTiO$_3$ substrate move the magnetic and ferroelectric domain walls in unison. Our experiments indicate an exponential increase of domain wall velocity with electric field strength and opposite domain wall motion for positive and negative field pulses. Magnetic fields do not affect the velocity of magnetic domain walls, but independently tailor their internal spin structure, causing a change in domain wall dynamics at high velocities.