Neutron scattering measurements of magnetic excitations in Gd/Y superlattices

Abstract

Neutron inelastic scattering has been used to measure the magnetic excitations as a function of applied magnetic field in an antiferromagnetically coupled Gd/Y superlattice. The excitations were measured along the c-axis, which is parallel to the normal of the interfaces and the sample growth direction. Dispersive spin waves were unambiguously detected on the application of a magnetic field. The spin waves are shown to renormalize with field following a basic model drawn from standard spin wave theory. The model required no free parameters aside from an initial amplitude.