In ${\mathrm{Mo}}_3$Ge, an $A15\mathrm{}$ superconductor with a low transition temperature of 1.45 K, $T_c$ is found to increase with increasing disorder. We also find that the density of states increases as $T_c$ increases. The transport properties indicate an "ideal" $T^5$ behavior with Matthiessen's rule being approximately obeyed, for small amounts of damage. For larger amounts of damage, saturation is found in the transport properties even though $\lambda$, the electron-phonon coupling, increases as is evidenced by the increasing $T_c$.

• Received 18 August 1978

DOI:https://doi.org/10.1103/PhysRevLett.41.1616