Small-angle neutron scattering by spatially inhomogeneous ferromagnets with a nonzero average uniaxial anisotropy

TL;DR

This paper extends micromagnetic small-angle neutron scattering theory to include global uniaxial anisotropy, enabling better analysis of spin-misalignment in ferromagnets with textured magnetic properties.

Contribution

The authors develop an analytical extension of existing scattering theory to incorporate global uniaxial anisotropy in ferromagnets, enhancing analysis capabilities.

Findings

Derived analytical expressions for cross-sections and response functions.

Validated theory with experimental data on Vitroperm and Ni.

Quantified uniaxial anisotropy quality factors in tested samples.

Abstract

Micromagnetic small-angle neutron scattering theory is well established for analyzing spin-misalignment scattering data of bulk ferromagnets. Here, this theory is extended to allow for a global uniaxial magnetic anisotropy (texture) of the material, in addition to the already included random zero-average local anisotropy. Macroscopic cross-sections and spin-misalignment response functions are computed analytically for several practically relevant mutual anisotropy and external magnetic field orientations in both parallel and perpendicular scattering geometries for field magnitudes both above and below the rotational saturation. Some of these expressions are tested on published experimental data of magnetic-field-annealed Vitroperm and plastically-deformed Ni, allowing to determine the corresponding global uniaxial anisotropy quality factors.