Measurements of phonon dispersion curves, specific heats, and superconductivity in 4d niobium alloys

Inelastic neutron scattering measurements of symmetry-direction phonon dispersion curves at room temperature in two Zr-Nb alloys and in a Zr-Nb-Mo alloy are presented along with their low-temperature specific heats and superconducting transition temperatures. The phenomenological charge-fluctuation model (CFM) is used to fit the curves and to generate the phonon density of states for each sample. Moments of this distribution along with T/sub c/ and N/sub bs/(0) are used to determine for comparison with Butler's rigid-muffin-tin calculations. Although numerical agreement is not expected and does not occur, nevertheless the general trend around Nb is reproduced. An analysis of the longitudinal-phonon contribution to lambda on basis of the CFM is presented. Finally the Zr-Nb-Mo alloy is found to behave in detail like a Nb-Mo alloy of the same electron per atom ratio both in its dispersion curves and in other properties indicating the importance of this parameter.