Simple Model for Characterizing the Electrical Resistivity inA−15Superconductors

A discussion of some of the difficulties with previous analyses of the resistivity of $A-15\mathrm{}$ compounds is given. Precise high-temperature data on $\alpha$-particle- and electron-damaged ${\mathrm{Nb}}_3$Ge and ${\mathrm{Nb}}_3$Sn samples with different defect concentrations are presented here and analyzed in a simple way with use of a phenomenological model based on the idea that the ideal resistivity must approach some limiting value in the regime where the mean free path becomes comparable to the interatomic spacing.