Upper critical fields, Hc2(T), and residual resistivities, 0, of Nb3Ge1-xSnx pseudobinaries with 0<~x<~1 produced by chemical vapor deposition were measured in fields up to 140 kG. The upper critical field Hc2(0) exhibits a minimum at x0.4. The temperature dependence of Hc2 for all ternary concentrations follows the theory of dirty type-II superconductors. The coefficient of the electronic specific heat, the band density of states Nb(0), and the electron-phonon coupling parameter are determined as a function of x and 0. Estimated electron-phonon coupling parameters suggest a high Fermi-surface average of McMillan's parameter I2 for Nb3Ge.
ASJC Scopus subject areas
- Condensed Matter Physics