SUPERCONDUCTIVITY IN PR-DOPED BI2CA2SR2CU3OY

Substitution of Pr at the Ca site in Bi1.6Pb0.4Ca2-xPrxSr2Cu3Oy, with 0 less than or equal to x less than or equal to 1, has been reported. Pr is shown to substitute in the (BiPb)-2223 system, albeit with a sim ultaneous formation of Pr-doped (BiPb)-2212 phase in the samples. The x-ray analysis indicates that the latter phase grows continuously with increasing Pr concentration up to x = 0.4. For x greater than or equa l to 0.4 only Pr-doped (BiPb)-2212 phase is observed in the samples. T he superconductor transition temperatures measured resistively shift t o lower temperatures, with increasing Pr, at a rate of 5 K/(% Pr). The normal-state resistivity value and its temperature dependence are fou nd to depend on the amount of Pr doping. We have further analysed the resistivity data of the pure and 5% (x = 0.1) doped samples for the fl uctuation conductivity. Both samples exhibit 2D behaviour for the supe rconducting order parameter in the critical regime, within the Aslamaz ov-Larkin formulation.