Journal of Electroanalytical Chemistry, Vol.378, No.1-2, 17-29, 1994
Power-Law Exponents and Hidden Bulk Relation in the Impedance Spectroscopy of Solids
Several aspects of the bulk response of disordered solids are investigated. The question is explored of how constant loss at the dielectric level, equivalent to the real part of the admittance being proportional to frequency, can occur. Such response is found to be possible for dielectric system response but is not likely for conducting system response. This kind of dielectric system behavior, which arises from the presence of a flat-top box probability distribution of activation energies, is further used to investigate and illustrate a promising alternating to Kronig-Kramers transformation of small-signal ac response data. For conducting system relaxation, the response of a possibly quite general dispersion equation, the Bryksin-Dyre-Macdonald (BDM) equation, an effective-medium approximation, is explored and used to illustrate how the underlying bulk dispersion of a material is obscured or hidden within the usual high frequency bulk semicircle present in impedance-level complex plane plots.
Keywords:ACTIVATION-ENERGIES;IONIC CONDUCTORS;AC CONDUCTION;DIELECTRIC RESPONSE;SODIUM TRISILICATE;FREQUENCY-RESPONSE;DISORDERED SOLIDS;RELAXATION;SYSTEMS;GLASSES