Berlin 2018 – scientific programme
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MA: Fachverband Magnetismus
MA 21: Poster I
MA 21.26: Poster
Tuesday, March 13, 2018, 09:30–13:00, Poster A
Non-reciprocal spin-wave dispersion in a NiFe/Ni bilayer — •Moritz Geilen1, Morteza Mohseni1, Thomas Brächer1, Yves Henry2, Damien Louis2, Matthieu Bailleul2, Florin Ciubotaru3, Burkard Hillebrands1, and Philipp Pirro1 — 1FB Physik and Landesforschungszentrum OPTIMAS, TU Kaiserslautern, Germany — 2Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, CNRS and Université de Strasbourg, B.P. 43, F-67037 Strasbourg Cedex 2, France — 3Imec, B-3001 Leuven, Belgium
Surface spin waves have an imaginary wave-vector component k⊥ across the film thickness, which leads to a localization of this mode to one surface of the film and the highly non-reciprocal propagation behaviour. This component is proportional to the in-plane wave-vector component k∥, which is perpendicular to the magnetization. But as long as both surfaces of the film are equal and the film itself has homogenous material parameters across its thickness the frequency of spin waves with wave vectors +k∥ and −k∥ are degenerate. This symmetry is broken in a magnetic bilayer system leading to frequency shift between counter-propagating spin waves.
We present the investigation of the spin wave spectrum of a Ni (25 nm) / NiFe (25 nm) bilayer film employing wave-vector resolved Brillouin light scattering spectroscopy and micromagnetic simulations. We find that the dispersion relation can be manipulated effectively, which is an important property for future magnonic computing devices.