SUPPRESSION FOR SUPERCONDUCTIVITY BY ZN DOPING IN RBA2CU3-XZNXO7-Y SYSTEMS (R=YB, ER, Y, DY, GD, EU, SM, AND ND)

Zn substituted RBa2Cu3-xZnxO7-y systems (R=Yb, Er, Y, Dy, Gd, Eu, Sm, and Nd) have been studied. The orthorhombic structure for these systems is retained in the studied range of substitution 0 less-than-or-equal-to x less-than-or-equal-to 0.1. The substitution of Zn for Cu causes a rapid nearly linear depression of superconducting transition T(c) with increasing Zn concentration x. When Zn content is kept constant, T(c) of RBa2Cu3-xZnxO7-y Was found to strongly depend on the ionic radius of the rare earth element R. This effect resembles to the ion size effect on T(c) in R1-xPrxBa2Cu3O7-y, where Pr substitutes the R site, and in RBa2Cu3-xGaxO7-y, where Ga substitutes Cu(1) sites in Cu-0 chains, although in the RBa2Cu3-xZnxO7-y systems Zn was found to substitute Cu(2) sites in Cu-O2 planes.