Large transport critical currents across boundaries in artificially joinedlarge-grain YBCO

Large-grain melt-processed YBCO has been joined to create nominally 'zero-a ngle' grain boundaries. Similar broadening of the resistive transition in b oth grains and the artificial boundary is observed in transport measurement s up to 7 T. Direct and pulsed currents are used to obtain the high-field v oltage-current characteristics which display power-law behaviour. The tempe rature and field dependence of the critical current in the boundary compare s well with that of the grain material. The large critical current densitie s, above 2000 A cm(-2) at 77 K for 4 T parallel to c-axis, show great promi se for the joining technology to produce large-scale engineering artefacts.