Stochastic Schemes of Dielectric Relaxation in Correlated-Cluster Systems

Abstract

Unlike the classical exponential relaxation law, the widely prevailing universal law with its fractional power-law dependence of susceptibility on frequency cannot be explained in the framework of any intuitively simple physical concept. The resulting constancy of the ratio of the imaginary to the real parts of the complex susceptibility, known as the ``energy criterion'', has a pleasing simplicity but the understanding of its origins needs a special theoretical treatment. A fresh light on the stochastic nature of the dielectric relaxation has been shed by a novel stochastic approach introduced in the last decade. Since the theoretical analysis involved is rather unfamiliar, the aim of this paper is to give some useful comments and suggestions which should help to follow in details the proposed stochastic scheme of relaxation leading to the well-known empirical responses. We justify the universality of the power-law macroscopic response as well as Jonscher's screening and energy criterion ideas, and we give a new basis to the research into the significance of relaxation processes.