SUPERCONDUCTIVITY AND STRUCTURAL TRANSITION IN MO-STABILIZED R(1-X)CA(X)SR(2)CU(3)O(Y) COMPOUNDS (R=PR, ND, AND Y)

Sr-based 123 compounds R(1-x)Ca(x)Sr(2)CU(2.7)Mo(0.3)O(y) with R = Pr, Nd, and Y are successfully stabilised by partial substitution of Mo f or Cu. A tetragonal-orthorhomic-tetragonal transition is observed for R = Y and Nd, which is induced by different oxygen content in the samp les. T-c of the samples is sensitive to the oxygen content other than the structure. For Pr-contained samples the resistivity decreases syst ematically with increasing the Ca dopant and oxygen content. The resul ts show that the hybridisation of the conduction electrons with the 4f band of Pr in Sr-based 123 compounds is weaker than that in Ba-based 123 compounds.