Regensburg 2010 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 17: Spin Dynamics / Spin Torque II
MA 17.13: Vortrag
Mittwoch, 24. März 2010, 17:45–18:00, H10
Direct imaging of current induced vortex gyration in an asymmetric potential well — •Andre Bisig1,2, Jan Rhensius1,3, Matthias Kammerer2, Michael Curcic2, Bartel Van Waeyenberge4, Kang Wei Chou5, Tolek Tyliszczak5, Stephen Krzyk1, Arndt von Bieren1, Hermann Stoll2, Gisela Schütz2, Laura Jane Heyderman3, and Mathias Kläui1 — 1Universität Konstanz, 78457 Konstanz, Germany — 2Max-Planck-Institut für Metallforschung, 70569 Stuttgart, Germany — 3Labor für Mikro- und Nanotechnologie, 5232 Villigen PSI, Switzerland — 4Ghent Univerity, 9000 Ghent, Belgium — 5Advanced Light Source, 94720 Berkeley LBNL, USA
Employing time-resolved scanning transmission x-ray microscopy (STXM), we investigate the dynamics of a pinned magnetic vortex domain wall in a magnetic nanowire. The gyrotropic motion of the vortex core is imaged in response to an exciting ac current. Using the analytical model of a two-dimensional harmonic oscillator, we determine the resonance frequency of the vortex core gyration by measuring the phase at various excitation frequencies. The elliptical vortex core trajectory at resonance reveals asymmetries in the local potential well that are correlated with the pinning geometry. Furthermore, we can measure the stiffness of the local potential well by determining the eccentricity of the vortex core trajectory at resonance. In the nanowire geometry, where the electrical contacts are placed far away from the area under investigation, Oersted field contributions are minimized.