This review emphasizes progress in understanding electrical conduction and related physical properties of a composite medium near a classical conductivity threshold - mostly but not entirely in the context of a percolation threshold. Besides dc conductivity, we discuss the dielectric susceptibility in a metal-dielectric composite, Hall effect and magnetoresistance in a good conductor - bad conductor mixture, conductivity fluctuations (flicker noise) in such a composite, and weakly nonlinear behavior in a composite dielectric. Scaling theories are described for the dielectric properties and for the magnetotransport near a percolation threshold. Because the conductivity fluctuations and weak nonlinearities are sensitive to microgeometric features that do no affect the linear conductivity, measuring them can provide new information about the microstructure.
|Number of pages||17|
|Journal||Physica A: Statistical Mechanics and its Applications|
|State||Published - 1 May 1989|