An analysis of dispersion measurements in percolative metal-insulator systems using analytic scaling functions

Continuous analytic scaling functions F+(omega/omega(c+)) and F-(omega/omega(c-)) for phi > phi(c) and phi < phi(c), are derived from a phenomenological equation for the complex conductivity of binary composites, which reduces to the standard percolation equations in most limits. These scaling functions and the real conductivity, for phi < phi(c), are compared with experimental results for several continuum percolation systems. The dispersion exponent for the real conductivity is found to be somewhat greater than 1 and close to (1 + t)ir. These results also show that the real dielectric constant, as a function of cb, has a frequency-dependent maximum at phi > phi(c). These last two results are in conflict with the standard percolation theory. (C) 2000 Elsevier Science B.V. All rights reserved.