CONDUCTION PROCESSES IN CRYSTALLINE NIXSI1-X FILMS

The electrical conductivity and magnetoconductance (MC) have been meas ured in crystalline nickel-silicon (c-NixSi1-x) films as a function of nickel content, x. An abrupt decrease in the conductivity is observed at the metal-insulator transition where x(c) approximate to 13.5 at.% Ni. The discontinuity is explained in terms of a percolation model. A bove 4 K, the magnetoconductance (MC) is negative and arises from an e lectron-electron interaction contribution and a weak-localization cont ribution involving strong spill-orbit scattering. Below 4 K, the magne toconductance rapidly becomes positive. These low-temperature MC data can be explained using a model of electrons scattering from superparam agnetic particles, first introduced by Gittleman et al.