Polarized Neutron Reflection: A Technique to Study Magnetization Profiles at Surfaces and Interfaces

The interaction of a neutron beam at grazing angle of incidence can be well described by the use of laws of classical optics when a refractive index is introduced. This follows from the undulatory nature of neutrons and from their interaction potential with matter. For polarized neutrons a magnetic material acts as a birefringent material and a magnetization profile can be inferred from reflectivity measurements. In this paper we will briefly describe the theory of polarized neutron reflection and some applications of this technique to study superconductors, thin and granular magnetic films.