CRITICAL FIELDS, PAULI PARAMAGNETIC LIMITING, AND MATERIAL PARAMETERS OF NB3SN AND V3SI

The upper-critical-field behavior of Nb3Sn and V3Si is studied as a function of residual resistivity. The results are analyzed in the framework of the Ginzburg-Landau-Abrikosov-Gor'kov theory of type-II superconductivity including the effects of the electron-phonon interaction. The importance of the electron-phonon interaction on the Pauli paramagnetic limiting process is stressed and it is found that inclusion of the electron-phonon corrections (most importantly the electron-phonon renormalization of the normal-state parameters) is needed to sensibly fit the data. For Nb3Sn failure to include these effects leads to too high spin-orbit scattering rates. The critical-field data are also used to determine the density of states of these materials as well as several other superconducting and normal-state parameters. © 1979 The American Physical Society.