Transport properties across high-angle bicrystals of melt-textured YBa/sub 2/Cu/sub 3/O/sub 6+x/

The transport properties of eight individual bicrystals in melt-textured YBa/sub 2/Cu/sub 3/O/sub 6+x/ were investigated in low and high fields at 4 K and 77 K. Bicrystals were cut from samples produced by the melt texture process with 10% and 20% added Y/sub 2/BaCuO/sub 5/. Misorientations between the crystals were determined by pole figure analysis, backscatter channeling patterns and light microscopy. The bicrystals exhibited a wide range of misorientations in both the ab planes and c-axis direction and all boundaries were high angle. Contrary to many reported expectations for melt-textured materials, all of the grain boundaries were weakly coupled. However, the strength of the coupling varied with misorientation angle and a weaker field dependence of J/sub c/ was observed in the samples with lower misorientation angle and lower grain boundary resistivity.<>