Structure, Low Temperature Conductivity, and Superconducting Properties of Niobium-Silicon Composite Films.
Niobium-silicon thin films have been fabricated using a duel electron gun, ultra high vacuum evaporator. Films with a layered or modulated structure were made as well as coevaporated niobium-silicon films with uniform composition. Transmission electron microscopy shows that both thin film materials are polycrystalline and have the niobium crystal structure. Sputtering -Auger depth profiles show that there is a large amount of interdiffusion at the niobium-silicon interfaces. Superconducting critical temperatures and critical magnetic fields were measured. An empirical relationship was found between the critical temperature and the bulk resistivity for the layered thin films. It is not clear what the theoretical explanation for this relation is. Temperature dependent conductivity and magnetoconductivity measurements were made on three and two dimensional films. These data were analyzed using superconducting fluctuation, weak localization, and electron-electron interaction theories. Good agreement between theory and experiment was obtained, giving values for the inelastic scattering time and for the spin-orbit scattering time.
- Pub Date:
- Physics: Condensed Matter