REALIZATION OF DIELECTRICS WITH A METAL-LIKE DISPERSION

Dielectrics with metal-like dispersion are realized by percolating networks' of submicrometer metal particles embedded in conventional dielectric materials. Their dielectric function epsilon = epsilon-1 - i-epsilon-2 was determined in the range 5 Hz less-than-or-equal-to omega/2-pi less-than-or-equal-to 10(10) Hz. A metal-like loss dispersion (epsilon-2 is-proportional-to omega--1) was measured over frequency intervals of up to eight orders of magnitude. The corresponding conductivities are many orders of magnitude lower than the bulk-metal values, however, they are still much higher than for known lossy dielectrics. Systems with a partial particle agglomeration, but no dc conductivity (no percolation), already show enhanced epsilon-2(omega) values, but no power law for the frequency dependence. This is in contrast with isolated particles, where epsilon-2(omega) = const holds.