Quantification of the magnetization arrangement of patterned films measured by polarized neutron reflectivity

Abstract

A periodic magnetic stripe array has been studied with a combination of real and reciprocal space methods: Kerr microscopy and polarized neutron reflectivity. The basic features of our experimental neutron data are well reproduced by a theoretical model using the distorted Born wave approximation and providing a set of parameters quantifying the magnetization arrangement in the stripe array system. While the specular neutron reflectivity measures a mean value of the optical potential averaged over a number of structural elements within the neutron coherence length, Bragg diffraction filters out magnetic correlation effects in the system of individual magnetic units within this length scale. Off-specular diffuse scattering probes correlations of magnetization fluctuations on a scale smaller than the coherence length. This altogether gives access to a detailed understanding of the magnetization arrangement which appears to be quite complex and hardly accessible by other methods.