Effect of Pb Substitution of Superconducting Transitions in Bi-Sr-Ca-Cu-O

For up to 40% substitution of Pb for Bi, the structure of the dominant phase remained unchanged accompanied by a decrease in the lattice parameters. The Pb substitution promoted the 110 K phase while addition of Ag gave rise to a sharper transition. The effect of substitution, Ag addition and heat treatment conditions can be ascribed to the optimisation of the Cu3+ concentration. 8 refs.