Conductivity studies were also made on samples of the same composition
and density. The electrical properties as a function of frequency
and temperature were determined by electrical impedance spectroscopy.
The complex impedance plots were analyzed by fitting with equivalent
circuits to obtain the resistance and capacitance as a function of
temperature. The total conductivity was calculated from the impedance
data and sample geometry. The equivalent circuit with resistance R and
constant phase element CPE were used to model the impedance spectrum.
Circuit parameters for the equivalent circuits were obtained by
using the least squares fitting routine in Zview (version 3.1c, Scribner
Associates Inc. USA). Conductivity data (total) obtained for the same
composition is given in Fig. 8.