EFFECT OF PR AND CA SUBSTITUTION ON SUPERCONDUCTIVITY IN Y(1-X-YPRXCAY)BA2CU3O7-DELTA

Pr substituted at constant Ca concentration for Y in (Y1-x-yPrxCay)Ba2 Cu3O7-delta superconductors have been prepared under identical conditi ons and the temperature dependence of the electrical resistivity of th ese samples are measured. The resistively determined values of T(c) de crease linearly with increasing x (0 less-than-or-equal-to x less-than -or-equal-to 0.2) for constant y = 0.10 and 0.15 which provides convin cing evidence that the suppression of superconductivity by Pr is mainl y due to magnetic pair breaking. The suppression of superconductivity can also be correlated to the observed changes in oxygen content deter mined by iodometric analysis and to the average Cu-valences. However, it is found that the observed suppression of T(c) cannot be compensate d by appropriate hole doping with Ca.