EFFECT OF LOW-LEVEL GE ADDITIONS ON THE SUPERCONDUCTING TRANSITION INPBTE-TL

A study is reported of the effect of low-level germanium additions (si milar to 0.01-0.1 at. %) on the parameters of the superconducting tran sition, viz. the critical temperature T-c, the second critical magneti c field H-c2, and /dH(c2)/dT/(T --> Tc) in PbTe doped with 2 at. % Tl, which are derived from the dependence of the electrical resistivity o f a sample on temperature (0.4-4.2 K) and magnetic field (0-1.3 T). Th e discontinuity revealed by experimental data is related to the onset of a Ge-induced structural phase transition. (C) 1998 American Institu te of Physics.