Neutron scattering on magnetic thin films: Pushing the limits (invited)

Abstract

Neutron scattering has been the scattering technique of choice for the analysis of magnetic structures and their dynamics for many decades. The advent of magnetic thin film systems has posed new challenges since such samples have inherently small scattering volumes. By way of examples, recent progress in the application of neutron scattering for the study of both magnetic structure and dynamics in magnetic thin film systems will be presented. First, a combined high angle neutron scattering and polarized neutron reflectivity investigation of the magnetic order of Cr and its influence on the exchange coupling between the Fe layers in Fe/Cr superlattices is discussed. It is shown that in the whole thickness range up to 3000 Å, the magnetic structure is governed by frustration effects at the Fe/Cr interfaces. Second, it is demonstrated that it is now possible to investigate the dynamic properties of magnetic thin films with neutron scattering. Unlike, e.g., Brillouin light scattering, inelastic neutron scattering provides access to large portions of the Brillouin zone. First results on spin wave excitations in a Dy/Y superlattice are presented.

Spin-polarized electron energy loss spectroscopy: a method to measure magnon energies

“…However, the interaction of neutrons with spin waves lacks any surface sensitivity and is so weak, that investigations of spin waves at surfaces or in single thin films are practically impossible [2]. Therefore the region of high energy and high wave vector spin waves is currently not explored in thin films and at surfaces.…”

Inelastic neutron scattering cross section in ferromagnetic nanowires

“…It is obvious that, compared to plain structures, the value of this decrease in two-dimensional superlattices is not so large. Roughly, it is of the same order as in multilayers, where inelastic neutron experiments have been successfully performed [8].…”

Neutron scattering studies of nanomagnetism and artificially structured materials

“…The magnon dispersion curves shown in Figure 10 demonstrate that measurements of inelastic excitations in nanostructured materials are feasible [154].…”