Berlin 2008 – scientific programme
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MA: Fachverband Magnetismus
MA 21: Magnetic Thin Films II
MA 21.11: Talk
Wednesday, February 27, 2008, 16:45–17:00, H 1012
Magnetic Excitations in Gd/Y and Dy/Y superlattices investigated with Inelastic Neutron Scattering — •Alexander Grünwald1,2, Elena Tartakovskaya3, Andrew Wildes2, Wolfgang Schmidt4, Katharina Theis-Bröhl5, Peter Link6, Roger Ward7, and Andreas Schreyer1 — 1GKSS-Research Centre Geesthacht, Germany — 2Institut Laue-Langevin, France — 3Institute for Magnetism, Ukraine — 4Jülich Centre for Neutron Science, Germany — 5Ruhr-Universität Bochum, Germany — 6TU München, Germany — 7University of Oxford, UK
Investigations of spin waves in magnetic superlattices are of great interest to understand fundamental properties of magnetism in confined structures. Inelastic neutron scattering is the most versatile technique to study magnetic excitations. The theory predicts discrete energy levels and Brillouin zone folding effects for spin waves propagating along the surface normal in rare earth superlattices. To compare with these calculations, we have investigated a number of Gd/Y and Dy/Y superlattices. Here we present inelastic neutron scattering measurements of low energy excitations. Clear dispersive modes from magnetic excitations and indications on discrete energy levels have been found in both superlattice compounds. The modes have a marked field dependence, particularly for the Gd/Y samples in which a spin wave gap is observed in moderate fields. The observations are in broad agreement with the theory.