Berlin 2005 – wissenschaftliches Programm
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MA: Magnetismus
MA 20: Poster:Schichten(1-29),Spintrsp(30-45),Ex-Bias(46-63),Spindyn(64-75),Mikromat.(76-80),Cluster(81-94),Abbv.(95-99),Obflm(100-02),SpElek.(103-09),E-Theo(110-14),Mikromag.(115-16),Spin+PÜ(117-26),Mag.Mat.(127-51),Meth.(152-55),Mol.Mag(156-59),Kondo(160-65
MA 20.69: Poster
Montag, 7. März 2005, 14:00–18:00, Poster TU C
Ferromagnetic resonance in mesoscopic rectangular permalloy structures — •P. Reuter, F. Giesen, and D. Grundler — Institut für Angewandte Physik und Mikrostrukturforschungszentrum, Universität Hamburg, Jungiusstr. 11, 20355 Hamburg, Germany
The magnetization dynamics of miniaturized ferromagnets is increasingly interesting for applications in magnetic storage devices. We have studied the dynamics of 20 nm thin ferromagnetic permalloy films shaped to squares (1× 1 µm2) and rectangles (1× 2 and 1× 4 µm2) using network-analyzer ferromagnetic resonance (FMR) measurements in the range of 45 MHz to 20 GHz at room temperature. By electron beam lithography and lift-off processing of thermally evaporated Ni80Fe20 the permalloy structures were deposited in arrays on broadband coplanar wave guides. In our devices we find several FMR modes which shift systematically with the applied in-plane magnetic field Hb and which reflect the different domain configurations. We attribute these modes to localized spin waves. FMR frequencies up to 13 GHz are observed at 90 mT, higher than the uniform precession mode of 10 GHz in an unpatterned permalloy film. Through aligning Hb in hard- or easy-axis direction we have addressed the dynamics originating from the bulk area and from the edge area, respectively. We thank D. Heitmann and J. Podbielski. Financial support by the BMBF via 13N8283 is gratefully acknowledged.