Inelastic scattering of neutrons by surface spin waves on ferromagnets

Abstract

We present a theoretical analysis of the inelastic scattering of thermal neutrons from the surface of a ferromagnetic crystal, under conditions where the angle of incidence of the neutron exceeds the critical angle and its wave function attenuates exponentially as one moves into the crystal. Under these conditions, we evaluate and compare the cross section for scattering off surface and bulk spin waves, for a model of a localized-spin ferromagnet. The formalism we use here should prove useful for analysis of a variety of similar problems.