| Thin amorphous films of Mo and Nb stabilized with nitrogen were prepared by e-beam deposition in an ultra high vacuum system. The film electrical characteristics were measured, as well as the tunneling characteristics of a junction between the film and a pre-deposited oxidized Al strip. The data were used to obtain the Eliashberg function (alpha)('2)F((omega)) by several computer methods. The resulting spectra were found to be in excellent agreement with computer model calculations of the phonon spectrum of amorphous metals by Rehr and Alben. However, these spectra differ from those of amorphous simple metals: The characteristic longitudinal and transverse phonon peaks have degenerated to one wide peak, and there is no apparent enhancement of the low energy end of (alpha)('2)F((omega)) which results in the "weak coupling" superconducting behaviour commonly observed in amorphous transition metals. In addition, the results were compared to theoretical calculations of the electron-phonon interaction in transition metals. |
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