Framework for Polarized Magnetic Neutron Scattering from Nanoparticle Assemblies with Vortex-Type Spin Textures

TL;DR

This paper develops an analytical framework for polarized magnetic neutron scattering from nanoparticle assemblies with vortex spin textures, linking magnetic correlations to vortex-axis distributions, validated by micromagnetic simulations.

Contribution

It introduces new analytical expressions for polarized SANS observables in nanoparticle systems with vortex spin structures, expanding understanding of magnetic correlations.

Findings

Analytical expressions for polarized SANS observables derived.

Connections established between magnetic correlations and vortex-axis distributions.

Validation of analytical results through micromagnetic simulations.

Abstract

Within the framework of the recently introduced multi-nanoparticle power-series expansion method for the polarized small-angle neutron scattering (SANS) cross section, we present analytical expressions for the polarized SANS observables arising from dilute nanoparticle assemblies with antisymmetric vortex-type spin structures. We establish connections between the magnetic correlation coefficients and the magnetic field-dependent vortex-axes distribution function, which is related to the random orientations of the magnetocrystalline anisotropy axes of the nanoparticles. Our analytical results are validated through a comparative analysis with micromagnetic simulations. This framework contributes to a comprehensive understanding of polarized magnetic neutron scattering from spherical nanoparticle systems exhibiting vortex-type spin structures.