# Fast vortex wall motion in wide Permalloy strips from double switching of the vortex core

## TL;DR

This paper investigates the high-velocity vortex wall motion in wide Permalloy strips caused by double switching of the vortex core, revealing a new dynamic mechanism that enhances domain wall mobility.

## Contribution

It provides a detailed micromagnetic simulation analysis of the double vortex core switching mechanism responsible for high-velocity vortex wall motion in wide strips.

## Key findings

- High-velocity plateau due to double vortex core switching
- Periodic vortex dynamics near strip edges
- Effect of structural disorder on vortex behavior

## Abstract

We study vortex domain wall dynamics in wide Permalloy strips driven by applied magnetic fields and spin-polarized electric currents. As recently reported [V. Est\'evez and L. Laurson, Phys. Rev. B, 93, 064403 (2016)], for sufficiently wide strips and above a threshold field, periodic dynamics of the vortex core are localized in the vicinity of one of the strip edges, and the velocity drop typically observed for narrow strips is replaced by a high-velocity plateau. Here, we analyze this behavior in more detail by means of micromagnetic simulations. We show that the high-velocity plateau originates from a repeated double switching of the magnetic vortex core, underlying the periodic vortex core dynamics in the vicinity of the strip edge, i.e., the "attraction-repulsion" effect. We also discuss the corresponding dynamics driven by spin-polarized currents, as well as the effect of including quenched random structural disorder to the system.