TY - JOUR A1 - Bisig, Andre A1 - Rhensius, Jan A1 - Kammerer, Matthias A1 - Curcic, Michael A1 - Stoll, Hermann A1 - Schütz, Gisela A1 - Van Waeyenberge, Bartel A1 - Chou, Kang Wei A1 - Tyliszczak, Tolek A1 - Heyderman, Laura J. A1 - Krzyk, Stephen A1 - von Bieren, Arndt A1 - Kläui, Mathias T1 - Direct imaging of current induced magnetic vortex gyration in an asymmetric potential well JF - Applied Physics Letters N2 - Employing time-resolved x-ray microscopy, 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. The elliptical vortex core trajectory at resonance reveals asymmetries in the local potential well that are correlated with the pinning geometry. Using the analytical model of a two-dimensional harmonic oscillator, we determine the resonance frequency of the vortex core gyration and, from the eccentricity of the vortex core trajectory at resonance, we can deduce the stiffness of the local potential well. Y1 - 2010 U6 - https://doi.org/10.1063/1.3373590 SN - 0003-6951 VL - 96 IS - 15 PB - AIP Publishing ER -