Dynamics of Vortex Nucleation in Nanomagnets with Broken Symmetry

TL;DR

This study explores how vortex nucleation occurs in asymmetric nanomagnets, demonstrating control over vortex properties using static magnetic fields and identifying robust nucleation modes applicable to various sub-100 nm structures.

Contribution

It introduces a simple model and numerical analysis of vortex nucleation in Pacman-like nanomagnets, revealing methods to control vortex chirality and polarity.

Findings

Controlled vortex chirality and polarity via in-plane magnetic fields

Identification of robust vortex nucleation modes

Applicability to a wide range of asymmetric nanomagnets

Abstract

We investigate fundamental processes that govern dynamics of vortex nucleation in sub-100 nm mesoscopic magnets. We focus on a structure with broken symmetry - Pacman-like nanomagnet shape - in which we study micromagnetic behavior both by means of a simple model and numerically. We show that it is possible to establish desired vortex chirality and polarity by applying only quasi-static in-plane magnetic field along specific directions. We identify the modes of vortex nucleation that are very robust against external magnetic field noise. These vortex nucleation modes are common among wide range of sub-100 nm magnets with broken rotational symmetry.