FREQUENCY-DEPENDENT PROCESSES IN DISPERSED SYSTEMS OF MESOSCOPIC PARTICLES

The frequency dependence between 100 Hz and 1 GHz and the temperature dependence of the complex dielectric function (DF) of heterostructures consisting of mesoscopic metal particles embedded in an insulating matrix have been investigated. By contrast with the situation above some GHz, where intra-particle processes dominate, at lower frequencies a separation of the DF into two contributions, from particles and from matrix, by means of an effective medium analysis, is not possible. The DF obeys the law epsilon" = epsilon' cotan(1/2-pi-eta) proportional nu-eta-1 with 0.8 less-than-or-equal-to eta < 1. Polarisation on the fractal metal-oil interface as well as inter-particle hopping may account for the observed behavior. Polymer matrices show weak relaxation processes, too.