Abstract
Crystal structures and superconductive properties of the solid solution Ba2Y1-xPrxCu3O7-y (0≤x≤1) are studied. Although Ba2Y1-xPrxCu3O7-y has an orthorhombic structure which is isomorphic with Ba2YCu3O7-y, Tc decreases monotonically with increasing Pr concentration, and superconductivity disappears at around x=0.6. The Rietveld analysis of X-ray powder diffraction data shows that both Cu(1)-O(3) bond length and the structural asymmetry of the Cu(2)O2 planes increase by the substitution of Pr for Y. Such structural changes induce the carrier density reduction and localization effects, which may cause the suppression of superconductivity in this system.