Magnetic vortices induced by a moving tip

TL;DR

This study numerically investigates how a moving magnetic tip can induce stable vortex structures in a ferromagnetic substrate, revealing robustness and transition phenomena influenced by excitations and domain walls.

Contribution

It demonstrates the formation and stability of magnetic vortices induced by a dipolar tip in a ferromagnetic substrate, including transition dynamics under high excitations.

Findings

Magnetic vortices become stable due to the tip's dipolar field.

Vortices are robust against tip motion-induced excitations.

Transitions between states occur at high excitation levels.

Abstract

A two-dimensional easy-plane ferromagnetic substrate, interacting with a dipolar tip which is magnetised perpendicular with respect to the easy plane is studied numerically by solving the Landau-Lifshitz Gilbert equation. Due to the symmetry of the dipolar field of the tip, in addition to the collinear structure a magnetic vortex structure becomes stable. It is robust against excitations caused by the motion of the tip. We show that for high excitations the system may perform a transition between the two states. The influence of domain walls, which may also induce this transition, is examined.