Velocity enhancement by synchronization of magnetic domain walls

TL;DR

This paper demonstrates that coupling and synchronization of magnetic domain walls in bilayers can significantly enhance their velocity, with tunable dynamics influenced by magnetic fields, advancing control over magnetic domain wall motion.

Contribution

The study introduces a novel bilayer system where coupled domain walls synchronize, leading to increased velocity and tunable dynamics, a new approach in magnetic domain wall control.

Findings

Coupled domain walls exhibit higher velocities than single walls.

Synchronization can be tuned from perfect to complete detuning.

Additional magnetic fields enable control over dynamic states.

Abstract

Magnetic domain walls are objects whose dynamics is inseparably connected to their structure. In this work we investigate magnetic bilayers, which are engineered such that a coupled pair of domain walls, one in each layer, is stabilized by a cooperation of Dzyaloshinskii-Moriya interaction and flux-closing mechanism. The dipolar field mediating the interaction between the two domain walls, links not only their position but also their structure. We show that this link has a direct impact on their magnetic field induced dynamics. We demonstrate that in such a system the coupling leads to an increased domain wall velocity with respect to single domain walls. Since the domain wall dynamics is observed in a precessional regime, the dynamics involves the synchronization between the two walls, to preserve the flux closure during motion. Properties of these coupled oscillating walls can be tuned by an additional in-plane magnetic field enabling a rich variety of states, from perfect synchronization to complete detuning.