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 ε=${\mathrm{\epsilon }}_1$-i${\mathrm{\epsilon }}_2$ was determined in the range 5 Hz≤ω/2π≤${10}^{10}$ Hz. A metal-like loss dispersion (${\mathrm{\epsilon }}_2$∝${\mathrm{\omega }}^{\mathrm{-}1}$) 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 ${\mathrm{\epsilon }}_2$(ω) values, but no power law for the frequency dependence. This is in contrast with isolated particles, where ${\mathrm{\epsilon }}_2$(ω)=const holds.