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TT: Tiefe Temperaturen
TT 8: Postersitzung I: Supraleitung
TT 8.9: Poster
Monday, March 8, 2004, 14:30–19:00, Poster A
Magneto-optic imaging of superconducting transport currents in magnetic environments — •Harald Jarzina, Volker Born, Christian Jooss, Eva Brinkmeier, Karsten Guth, Wilko Westhäuser, and H. C. Freyhardt — Institut für Materialphysik, Tammannstrasse 1, 37073 Göttingen
Magneto optic (MOI) imaging provides a valuable tool for space and time resolved measurements of the flux density distribution of superconducting films. For technological applications such as coated conductors, the investigation of transport currents is of special interest. In coated conductors, grain boundaries are the main reason for current suppression.
In this work, we present flux and current-density distributions of YBa2Cu3O7 strips on single and bicrystalline substrates with an applied transport current. We discuss the change in the flux density distribution if a soft magnetic material is brought into the vicinity of the film. In the case of magnetization currents, the presence of soft magnetic material at the edges of the superconductor can prevent flux entry into the superconductor, thus stabilizing the Meissner phase up to higher external fields. Thereby current densities larger than the pinning determined critical current density jc can be obtained.