Framework for polarized magnetic neutron scattering from nanoparticle assemblies with vortex-type spin textures

The authors derive here analytical expressions for the polarized magnetic neutron scattering cross section and the related pair-distance distribution function arising from dilute nanoparticle assemblies with antisymmetric vortex-type spin structures. Connections between the magnetic correlation coefficients and the field-dependent vortex-axes distribution function are established. The results, which are validated through a comparative analysis with micromagnetic simulations, replace the conventional formulation for the macrospin model and provide a framework for the analysis of experimental neutron data.