Berlin 2005 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 36: Superconductivity - Vortex Dynamics, Vortex Phases, Pinning
TT 36.8: Vortrag
Mittwoch, 9. März 2005, 12:00–12:15, TU H2053
Charge density distributions induced by flux creep in superconducting YBCO films — •Volker Born and Christian Jooss — Institut für Materialphysik, Friedrich-Hund-Platz 1, 37077 Göttingen
A moving vortex in a superconductor represents an electric dipol where the induced charge is distributed over its spatial magnetic extension. On mesoscopic length scales of ≈ 1µm (averaging over the spatial structure of individuals vortices) all dipols cancel, if ensembles of vortices move homogeneously. However, a mesoscopic charge density distribution arises if gradients of the vortex velocity perpendicular to their direction of motion exist. An excellent tool to study these charge densities is time and space resolved magneto-optics with spatial resolutions down to ≈ 1µm. Here, we report on charge densities being induced into superconducting YBa2Cu3O7 thin films by thermally activated flux creep in constant external magnetic fields. We discuss briefly our method how to obtain the total electric field, the polarisation distribution and the charge density distribution. The main focus is directed to the vortex motion at current domain boundaries, grain boundaries and circular defects which builds up complex patterns of charge density distributions.