Critical currents of PbBiSCCO Ag/AgCu composites

The superconducting properties of PbBiSCCO containing 10, 20 or 30 wt% of Ag-4 at% Cu additions, as compared to Ag additions, are reported. The highest critical currents have been found for both the 10 wt% Ag-4 at% Cu and Ag composites after 24 h annealing, which are about three times higher than the value measured for pure PbBiSCCO, SEM/EDAX shows that a connectivity effect can account for this finding. The observed superiority of the Ag composites over the Ag-4 at% Cu composites is discussed in terms of the supercurrent transport properties versus interfacial effects.