Magnetic neutron scattering by magnetic vortices in thin submicron-sized soft ferromagnetic cylinders

Using analytical expressions for the magnetization textures of thin submicron-sized magnetic cylinders
in vortex state, we derive closed-form algebraic expressions for the ensuing small-angle neutron
scattering (SANS) cross sections. Specifically, for the perpendicular and parallel scattering geometries,
we have computed the cross sections for the case of small vortex-center displacements without
formation of magnetic charges on the side faces of the cylinder. The results represent a significant
qualitative and quantitative step forward in SANS-data analysis on isolated magnetic nanoparticle
systems, which are commonly assumed to be homogeneously or stepwise-homogeneously
magnetized. We suggest a way to extract the fine details of the magnetic vortex structure during the
magnetization process from the SANS measurements in order to help resolving the long-standing
question of the magnetic vortex displacement mode.