We report new measurements of the normal-state electrical resistances of several high-$T_c$ (∼ 20 K) $A-15$ structure superconductors. It is found that the resistances are linear functions of $T^2$ from $T_c$ to 40 K. Analysis of available lattice heat-capacity data on the same materials shows that it also varies as $T^2$ over the same temperature interval. These observations suggest that the $T^2$ resistivity is due to electron-phonon scattering. This interpretation is supported by the results of a model calculation for the temperature dependence of the resistivity and the lattice-heat capacity of ${\mathrm{Nb}}_3$Sn.

• Received 8 March 1976

DOI:https://doi.org/10.1103/PhysRevB.15.2624