Berlin 2005 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 36: Superconductivity - Vortex Dynamics, Vortex Phases, Pinning

TT 36.9: Vortrag

Mittwoch, 9. März 2005, 12:15–12:30, TU H2053

Investigation of the j_c(T)-behavior to answer the question of pinning in YBa₂Cu₃O_7−δ thin-films — •Sebastian Brück¹ and Joachim Albrecht^1,2 — ¹Max-Planck-Institut für Metallforschung, Heisenbergstrasse 3, D-70569 Stuttgart, Germany — ²Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany

Thin films of the high-temperature superconductor YBa₂Cu₃O_7−δ (YBCO) grown on SrTiO₃ (STO) substrates which partly experience a moderate nanostructuring of the surface, show an imposing increase of the critical current density where the surface is treated. The magneto-optical imaging technique joint by a numerical inversion scheme is used to obtain the current density distribution in such films with high spatial resolution enabling one to directly compare j_c in different parts of the sample. It will be shown that a detailed investigation of the temperature behavior of j_c, taking into account the distinctions between untreated and structured part, can provide deeper insights into the actual pinning scenario. By comparing the experimental results with theoretical models, evidence is found for the important role of intergranular low-angle grain boundaries for the increase of j_c as well as for the pinning scenario in general.