Localization and Electron Interaction Effects in Thin Films: Palladium, Platinum, Gold.
Results are presented from a series of experiments designed to probe the effects of electron localization on the conductivity of thin metal films. The films are made of Pd, Pt, and Au, sputtered onto Si or glass substrates. Some Au films are doped with Fe impurities. Thicknesses vary from six to several hundred angstroms. Conductivity and magnetoresistance are examined for temperatures from .08 to 72(DEGREES)K, and fields to 19T. Historical and theoretical background is provided for both localization and electron interaction effects. The theory is extended to include new situations observed in the experiments. Results indicate that smooth films exhibit symplectic localization with a T('2) elastic scattering rate. Interaction effects are also present. Smooth films of Pd are superconducting at T(, )<(, ).5K. They exhibit an anomalous magnetoresistance amplitude reduction for T(, )<(, )5(DEGREES)K due to dimensional crossover of spin-orbit scattering. Rough films exhibit anomalous orthogonal localization, isotropic with respect to field orientation, arising from granular surface structure. The reduced localization contribution permits observation of spin relaxation in the interaction contribution in rough Pt. Both Kondo and localization effects are found in Au:Fe films.
- Pub Date:
- Physics: Condensed Matter