ELECTRON-ELECTRON INTERACTION AND NORMAL-STATE TRANSPORT IN SUPERCONDUCTING TI-(SN,GE) ALLOYS

We have measured the resistivity as a function of temperature, rho(T), of superconducting Ti-1-x(Sn,Ge)(x) (0.03 less than or similar to x l ess than or similar to 0.12 for Ti-Sn and 0.03 less than or similar to x less than or similar to 0.07 for Ti-Ge) alloys below 25 K. These al loys are chosen because, upon dilute alloying, their impurity resistiv ities rho(0) vary readily from approximate to 55 to approximate to 150 mu Omega cm, while their superconducting transition temperatures T-c increase moderately by a factor similar to 60%. We find that the overa ll behavior of rho(T) can be quantitatively interpreted in terms of th e Boltzmann transport AT(n) (with A being a constant and n an exponent ) plus a temperature-dependent contribution Delta rho(I) arising from electron-electron interaction effects in the presence of disorder. Par ticularly, we observe a disorder dependence of Delta rho(I) similar to rho(0)(5/2). We also observe that the screened Coulomb interaction pa rameter (F) over tilde, defined in the electron-electron interaction t heory, becomes much more negative in samples with increasing T-c.