Magnetic neutron scattering from spherical nanoparticles with Neel surface anisotropy: Atomistic simulations

TL;DR

This paper uses atomistic simulations to study how Neel surface anisotropy affects the magnetization and neutron-scattering response of spherical nanoparticles, providing insights for experimental analysis.

Contribution

It introduces a numerical approach to incorporate Neel surface anisotropy in modeling neutron scattering from spherical nanomagnets, extending previous analytical models.

Findings

Neel surface anisotropy significantly influences neutron-scattering patterns.

Size distribution effects alter the scattering response.

Numerical results align with and extend analytical expressions.

Abstract

We consider a dilute ensemble of randomly-oriented noninteracting spherical nanomagnets and investigate its magnetization structure and ensuing neutron-scattering response by numerically solving the Landau-Lifshitz equation. Taking into account the isotropic exchange interaction, an external magnetic field, a uniaxial magnetic anisotropy for the particle core, and in particular the Neel surface anisotropy, we compute the magnetic small-angle neutron scattering cross section and pair-distance distribution function from the obtained equilibrium spin structures. The numerical results are compared to the well-known analytical expressions for uniformly magnetized particles and provide guidance to the experimentalist. Moreover, the effect of a particle-size distribution function is modeled.