Dynamics of a domain wall in a magnetic nanostrip: a toy model

TL;DR

This paper presents a simple theoretical model describing the complex dynamics of vortex domain walls in ferromagnetic nanostrips under external magnetic fields, revealing three distinct motion regimes and matching experimental observations.

Contribution

Introduces a toy model capturing the three dynamical regimes of vortex domain wall motion in ferromagnetic nanostrips under magnetic fields.

Findings

Identifies three regimes: viscous, underdamped oscillatory, and high-field linear drift.

Derives velocity-field relationships for each regime.

Matches model predictions with experimental data.

Abstract

In this report we demonstrate a simple model for the motion of a vortex domain wall in a ferromagnetic strip of submicron width under the influence of an external magnetic field. The model exhibits three distinct dynamical regimes. In a viscous regime at low fields the wall moves rigidly with a velocity proportional to the field. Above a critical field the motion becomes underdamped as the vortex moves periodically across the strip; these oscillations are accompanied by a slow drift with a decreasing velocity. At still higher fields the drift velocity starts rising linearly with the field again but with a much lower mobility dv/dH than in the low-field regime. We calculate the relevant quantities and compare them to experimentally observed values.