EXPERIMENTAL-EVIDENCE FOR ELECTROMAGNETIC COUPLING INHOMOGENEITY ALONG THE GRAIN-BOUNDARY PLANE IN HIGH-ANGLE MELT-TEXTURED YBA2CU3O6+X

Detailed characterization of two high angle general misorientation YBa 2Cu3O6+x bicrystals produced by the melt-texture-liquid-phase-removal method shows that the boundaries contain regions of both strong and we ak coupling, In one bicrystal the strongly coupled component was infer red from analysis of the magnetic-field-dependent voltage-current char acteristics and confirmed with magneto-optical images of the boundary. Several sections of the second sample having macroscopically differen t grain boundary facets were tested after sectioning with a laser. The properties were not dependent on the grain boundary plane orientation . High-field, high-sensitivity voltage-current characteristics of the inter and intra-grain regions had qualitatively identical properties a nd confirmed that there was a substantial strong coupled component to the boundary. The data confirm that the melt-texture-liquid-phase-remo val method of YBa2Cu3O6+x formation is beneficial to the formation of strong-coupling regions in high angle grain boundaries and that some h igh angle grain boundaries contain strongly coupled components.