ELECTRICAL-RESISTIVITY AND XRD MEASUREMENTS ON YBCO-PBS HTS SYSTEM

Electrical resistivity and XRD measurements are reported for HTS samples with starting composition Y1Ba2(Cu1-xPbx)3S3xOy (0 less-than-or-equal-to x less-than-or-equal-to 0.20). It is elucidated that the substituted compounds (0 < x less-than-or-equal-to 0.05) have improved processibility and normal state properties (e.g., better intergrain linkage) and a peculiar characteristic trend of variation in superconducting proper-ties like transition temperature (T(c)) and transition width (DELTA-T(c)), at the cost of lowering T(c) by hardly a few K. For x > 0.05 samples, however, the evolution of impurity phases like Y2Ba1Cu1O5 and BaPbO3 suppresses the superconducting properties. The probable explanation of these results is also discussed. It is found that perhaps the sulphur of PbS substitutes for oxygen in the YBCO-lattice, however, Pb does not, it mainly forms the impurity phase BaPbO3.