Low Temperature Specific Heat Studies of Molybdenum-Ruthenium Based Superconducting Metallic Glasses

Citation

Hopkins, Stuart Thomas (1983) Low Temperature Specific Heat Studies of Molybdenum-Ruthenium Based Superconducting Metallic Glasses. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/TJRF-S955. https://resolver.caltech.edu/CaltechETD:etd-10102002-125642

Abstract

Low temperature specific heat measurements have been used to investigate the electronic structure and superconducting properties of metallic glasses based on transition metals Mo and Ru alloyed with metalloids B and Si. An apparatus constructed for making these measurements is described. The results obtained are discussed in terms of the dependence of the density of states at the Fermi level N(ε_F) and of the Debye temperature θ_D on metalloid content, and the influence of these parameters on observed properties. N(ε_F) is shown to reflect the short-range order of the metal atoms and in Mo-Ru-B alloys, indicates the existence of two distinct amorphous phases. In addition, N(ε_F) strongly influences the superconductivity and electronic properties of these materials. Alloying with metalloids increases the Debye temperature of the amorphous Mo-Ru phase and thus affects the superconductivity through the dependence of the electron-phonon coupling on average phonon frequency. A comparison with elastic properties shows an anomalous effect in the lattice specific heat commonly observed in insulating glasses.

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