The influence of phase probability distributions on impedance spectroscopy

The brick layer model is normally employed in impedance spectroscopy calculations when the material system is homogeneous. Here, we use probability distributions to modify this model for real inhomogeneous materials. In the plot of Z' against Z''/f we find that the straight lines change into curves for inhomogeneous phases. We can also distinguish between the effects of overlap and the effects of distribution from the shape of the plot. By fitting the impedance spectra, we can evaluate the degree of homogeneity of the phase. Analysis of a negative temperature coefficient ceramic shows that the new model can fit real experimental data very well.