Asymmetric hysteresis of N\'eel caps in flux-closure magnetic dots

TL;DR

This study explores the asymmetric hysteresis behavior of Nel caps in flux-closure magnetic dots, revealing the influence of geometric asymmetry on magnetization reversal mechanisms through experimental imaging and simulations.

Contribution

It demonstrates how geometrical asymmetry in magnetic dots affects Nel cap switching, combining experimental imaging with micromagnetic simulations to uncover new insights.

Findings

Most dots show symmetric magnetization reversal

Some dots exhibit pronounced asymmetric hysteresis

Geometrical features strongly influence switching mechanisms

Abstract

We investigated with XMCD-PEEM magnetic imaging the magnetization reversal processes of N\'eel caps inside Bloch walls in self-assembled, micron-sized Fe(110) dots with flux-closure magnetic state. In most cases the magnetic-dependent processes are symmetric in field, as expected. However, some dots show pronounced asymmetric behaviors. Micromagnetic simulations suggest that the geometrical features (and their asymmetry) of the dots strongly affect the switching mechanism of the N\'eel caps.