Micromagnetic simulation of small-angle neutron scattering from magnetic recording media

Abstract

A micromagnetic simulation of the magnetic morphology of CoCrPtB based longitudinal recording media is used to model small-angle neutron scattering data and provide a quantitative description of the local flux density in these nanostructured magnetic materials. The model addresses several aspects of the experimental measurements and, in particular, explains an unusual increase in scattering along the applied field direction for certain values of the scattering vector q. The increased scattering along the field direction results in a change of the phase of the angular variation of the scattering by 90∘. This 90∘ change in scattering phase arises naturally from the influence of stray fields when modeling the media as a heterogeneous alloy consisting of grains with a high saturation magnetization core and a permeable shell.