Superconducting Tunneling in the Amorphous Transition Metals Mo and Nb

The results of a tunneling experiment in thin films of amorphous Mo and Nb stabilized with ${\mathrm{N}}_2$ are presented. The data were analyzed by several methods to obtain the Eliashberg function, ${\alpha }^{2}F\left(\omega \right)$. The resulting spectra are qualitatively different from ${\alpha }^{2}F\left(\omega \right)$ of amorphous simple metals, and in good agreement with computer model simulation of Rehr and Alben of the phonon spectrum of amorphous transition metals.