Transport properties of bulk-bicrystal grain boundaries in artificially joined large-grain YBCO

A technique for joining large-grain YBCO has been used to produce bulk-bicrystal grain boundaries of different orientations. The behaviour of boundaries nominally of 0/spl deg/[100], 0/spl deg/[001] and asymmetric 15/spl deg/[100]-tilt misorientation have been investigated using low frequency transport measurements in fields up to 7 T. The boundaries exhibit a metallic normal state and a superconducting transition which broadens with increasing field having an irreversibility line which closely matches that of the adjoining grains. This same qualitative behaviour is seen in all the samples measured for field applied parallel and perpendicular to the c-axis and up to the highest current densities employed (20 Acm/sup -2/). Variation between the different samples due to microstructural differences are discussed. We interpret these results as strong suggestive evidence that this joining technique can be used to produce strongly-coupled large-grains for bulk-scale engineering applications.