Probing fractal magnetic domains on multiple length scales in Nd2Fe14B

TL;DR

This study uses small-angle neutron scattering to reveal fractal magnetic domain structures in Nd2Fe14B, linking surface patterns to bulk properties and explaining anomalous magnetization behavior.

Contribution

It demonstrates the presence of fractal magnetic domains in Nd2Fe14B across multiple length scales, connecting surface microscopy with bulk neutron scattering data.

Findings

Magnetic domain structures extend from surface to bulk

Domains exhibit fractal features down to 6 nm

Explains anomalous magnetization increase below spin-reorientation transition

Abstract

Using small-angle neutron scattering, we demonstrate that the complex magnetic domain patterns at the surface of Nd2Fe14B, revealed by quantitative Kerr and Faraday microscopy, propagate into the bulk and exhibit structural features with dimensions down to 6 nm, the domain wall thickness. The observed fractal nature of the domain structures provides an explanation for the anomalous increase in the bulk magnetization of Nd2Fe14B below the spin-reorientation transition. These measurements open up a rich playground for studies of fractal structures in highly anisotropic magnetic systems.