STUDY ON THE SUPERCONDUCTIVITY IN Y1-XPRXBA2CU3-YLIYO7-DELTA

Polycrystalline samples of Y1-xPrx Ba2Cu3-yLiyO7-delta (Y = 0, 0.05) h ave been prepared and characterized by X-ray powder diffraction and te mperature dependence of resistivity. The T-c of Y1-xPrxBa2Cu2.95Li0.05 O7-delta decreases monotonically with increasing Pr content, but the n ormalized T-c (T-c/T-c(max)) of Y1-xPrxBa2Cu2.95Li0.05O7-delta is high er than that of Y1-xPrxBa2Cu3O7-delta for a fixed Pr content. This res ult indicates that the effect of T, suppression by Pr doping becomes w eaker in the Li-doped system. Considering the Li substitution effect o n the structural details, we argue that the Pr-O covalent bonding effe ct is responsible for the superconductivity suppression.