Fractional vortices and composite domain walls in flat nanomagnets

TL;DR

This paper explains complex magnetic patterns in ferromagnetic nanostructures by identifying elementary topological defects, such as vortices and edge-confined vortices, and describes domain walls as composite objects of these defects.

Contribution

It introduces a simple topological framework for understanding magnetic patterns in nanostructures, highlighting elementary defects and their role in domain walls.

Findings

Identification of elementary topological defects in magnetization fields

Explanation of domain walls as composites of elementary defects

Insight into magnetic pattern formation in nanostructures

Abstract

We provide a simple explanation of complex magnetic patterns observed in ferromagnetic nanostructures. To this end we identify elementary topological defects in the field of magnetization: ordinary vortices in the bulk and vortices with half-integer winding numbers confined to the edge. Domain walls found in experiments and numerical simulations in strips and rings are composite objects containing two or more of the elementary defects.