Magnetic field dependence of critical currents of single grain boundary junctions in Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub 7- delta / superconductor

The authors present data on the magnetic field dependence of critical currents in epitaxial films of Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub 7- delta / containing a single boundary. The data are obtained as a function of temperature, the orientation of the grain boundary, and magnetic fields of up to 5 T. A significant residual critical current is observed which increases with decreasing angle of misorientation at a given field and temperature. The data are in qualitative accord with a model in which the grain boundary comprises a large number of microbridges in parallel.<
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