Impedance spectroscopy of Na and Nd doped strontium bismuth titanate

Abstract Sr 0.2 Na 0.4 Nd 0.4 Bi 4 Ti 4 O 15 is prepared by Sol‐Gel route using the modified polymeric precursor method based on the Pechini process and its electrical properties are investigated by Complex Impedance Spectroscopy (CIS). Results are presented in two ways, complex plane plots (real versus imaginary) and spectroscopic plots (real and imaginary against frequency). CIS has provided convincing evidence for the existence of both grain (bulk) and grain‐boundary effects that were separated in the frequency domain of the impedance spectrum. Experimental data are fitted to two parallel RC equivalent circuits in series. The values of resistance and capacitance of bulk and grain boundary contributions are also calculated. Relaxation times are calculated for both grains and grainboundaries. Conduction and charge carrier behaviors are studied from frequency and temperature dependence of ac conductivity. The ac conductivity follows a two‐power law behavior at different temperatures with frequency exponents s 1 and s 2 . (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)