The superconducting transition temperatures of some dilute lead alloys

Abstract

Measurements have been made of the change in Tc produced by small additions of Cd, Hg, In, Tl, Sn, (TlB1), Sb and Bi to lead. For the ternary isoelectronic Pb(TlB1) system a good fit of the data can be made to the Markowitz and Kadanoff model of anisotropy and valence contributions to δTc, and this yields a mean square anisotropy <a2> of 0.004. This quantity has been used to derive valence contributions for the binary alloys, but these differ from values calculated on simple assumptions.