Maxwell-Wagner Polarization in Sintered Compacts of Ferric Oxide

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Abstract
A method is presented for the analysis of relaxation spectra resulting from Maxwell‐Wagner interfacial polarization in sintered oxide compacts. Using a multilayer model to represent ferric oxide pellets, containing heterogeneities induced by the sintering process, a distribution function of the relaxation times is derived which, when applied to the Maxwell‐Wagner equation for a simple two‐layer capacitor, gives an equation empirically found to describe the dielectric properties of the samples. Data are presented to show the close parallel between the distribution of relaxation times, predicted by the distribution function, and the distribution of resistivities found to be present in the samples from dc measurements. Comparisons are made between the data predicted by the analytical equations and those obtained from experimental methods. It is concluded that the use of a distribution function of the relaxation times for the analysis of the relaxation spectra is physically justifiable and that the multilayer model in conjunction with an asymmetric distribution function is capable of accurately describing the relaxation spectra observed in sintered compacts of α‐Fe2O3.