Regensburg 2010 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 23: Micro- and Nanostructured Magnetic Materials III
MA 23.3: Vortrag
Donnerstag, 25. März 2010, 10:45–11:00, H3
Anisotropic stray field effect on magneto-dynamic properties of square element arrays — •Claudia Patschureck1, Manfred Wolf1, Jeffrey McCord1, Rudolf Schäfer1, Ludwig Schultz1, Ingolf Mönch1, Oliver Schmidt1, Konstantin Kirsch2, and Roland Mattheis2 — 1Leibniz Institute for Solid State and Materials Research Dresden, Helmholtzstraße 20, 01069 Dresden — 2Institute of Photonic Technology e.V., POB 100239, 07702 Jena
The role of stray-field interaction on the magneto-dynamic properties of quasi-saturated arrays of square Permalloy thin film elements is presented. The lateral element size ranges from 20 to 100 µm with a constant inter-element spacing of 10 µm and film thicknesses of 50 and 100 nm. The frequency of the uniform resonance mode was found to be enhanced compared to an extended reference film. Although square elements can be, in first approximation, considered to be isotropic and to have equal demagnetizing factors Nx and Ny along the element main axes, an additional positive contribution to the effective field was measured. This is in contrast to Kittel’s equation which predicts a change of the resonance frequency in case of Nx unequal Ny. It is found that the resonance frequency shift decreases with increasing element size and decreasing film thickness. The additional effective field contribution is attributed to anisotropic stray field coupling of neighbouring elements. A model of interacting dipoles is presented that qualitatively describes the experimental results.