Substitution of transition metals for Cu in Bi-2(SrCa)(n+2)Cun+1Oy whiskercrystals: Fe and Pd - art. no. 184515

We have measured the resistive superconducting transition temperature of si ngle-crystal whiskers of Bi2SrCa)(n+2)(Cu1-xMx)(n+1)O-y in which M represen ts the transition metals Fe and Pd that have been partially substituted for Cu. Combining these measurements with our earlier results far Co, Ni, and Zn substitutes, we derive a general relationship for the rate at which T-C is depressed by substitution of transition metals: dT(C)/dx approximate to - 780 K for all these elements and both the 2212 (n = 1) and 2223 (n=2) pha ses. Further, the normalized residual resistance is also a universal functi on of x. This is contrary to what others find for YBa2Cu3O7-delta (YBCO), i n which Zn and Ni substitutions act quite differently on dT(C)/dx. The expl anation of this effect in YBCO apparently does not involve the general beha vior of the Cu-O planes. The magnitude of dT(C)/dx is about half that predi cted by the Abrikosov-Gorkov relation, as seen in other Cu-O superconductor s.