Experimental evidence for electromagnetic coupling inhomogeneity along the grain boundary plane in high angle melt-textured YBa/sub 2/Cu/sub 3/O/sub 6+x/ bicrystals

Detailed characterization of two high angle general misorientation YBa/sub 2/Cu/sub 3/O/sub 6+x/ bicrystals produced by the melt-texture-liquid-phase-removal method shows that the boundaries contain regions of both strong and weak coupling. In one bicrystal the strongly coupled component was inferred from analysis of the magnetic-field-dependent voltage-current characteristics and confirmed with magneto-optical images of the boundary. Several sections of the second sample having macroscopically different 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 and confirmed that there was a substantial strong coupled component to the boundary. The data confirm that the melt-texture-liquid-phase-removal method of YBa/sub 2/Cu/sub 3/O/sub 6+x/ formation is beneficial to the formation of strong-coupling regions in high angle grain boundaries and that some high angle grain boundaries contain strongly coupled components.<>