Berlin 2008 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 26: Spin Dynamics / Spin -Torque II
MA 26.3: Vortrag
Donnerstag, 28. Februar 2008, 15:00–15:15, EB 301
Direct observation of the excitation phase of microwave excited spin waves — •Thomas Schneider1, Alexander A. Serga1, Timo Neumann1, Burkard Hillebrands1, and Mikhail P. Kostylev2 — 1Fachbereich Physik und Forschungsschwerpunkt Minas, TU Kaiserslautern, Erwin-Schrödinger-Str. 56, 67663 Kaiserslautern, Germany — 2School of Physics, M013, University of Western Australia, 35 Stirling Highway, Crawle, WA 6009, Australia
We report on phase resolved Brillouin light scattering spectroscopy investigations of the excitation of spin waves by microwave pulses. We observed the phase difference between two counterpropagating waves with antiparallel wavevectors excited by the same microwave current flowing through a microstrip spin-wave antenna (the so called "excitation phase"). Theory predicts that for the backward volume mode (spin-wave propagation parallel to the applied bias field) this excitation phase should be equal to π since they are excited by the out-of-plane component of the microwave field. By measuring the phase accumulation (i.e. the change of phase with propagation distance) we were able to experimentally confirm that value. If one changes the propagation direction to perpendicular to the applied field (Damon-Eshbach mode) while the amplitude of the two waves becomes drastically unsymmetrical our experiments show that the phase becomes symmetrical (excitation phase equals zero). Theoretical analysis confirms this effect.
Financial support by the DFG, the Graduiertenkolleg 792 and the Australian Research Council is gratefully acknowledged.