Abstract:
The co-doping effect of Zn and Pr impurities in the compound of composition Y(1-x)Pr(x)Ba(2)[Cu(1-y)Zn(y)](3)O(7-delta) with x = 0.1, x = 0.2 and 0 less than or equal to y less than or equal to 0.1 has been investigated by analyzing the results of electrical resistivity measurements. It is found that for Pr substitution at x less than or equal to 0.1, there is a minimal influence on in-plane processes, thereby slightly affecting T-c and residual resistivity rho(0), but with the resistivity slope d rho/dT becoming large for the range of y from 0.03 to 0.06, leading to a larger depinning effect. For x = 0.2 a drastic change is observed whereby rho(0) becomes abnormally large, and d rho/dT becomes negative, implying totally pinned charge stripes and no depinning. The second observation therefore suggests that Pr substitution converts the overdoped system to an optimally doped system, leading to the universal superconductor-insulator transition.
