Characterization of electrical behaviour of Si modified BaSnO3 electroceramics using impedance analysis

The compounds BaSn1–xSixO3 (x = 0–15 mol%) have been prepared by high temperature solidstate reaction route. Powder X-ray diffraction pattern of the samples reveal the formation of a single phase solid solution. It was found that single phase compositions have a cubic crystal structure similar to that of pure barium stannate at room temperature. The a.c. impedance analysis has been carried out in the frequency range 100 Hz–1 MHz for temperature ranging from 300 K to 750 K. Analysis of a.c. impedance data using the complex impedance plane gives the a.c. and d.c. resistance of negative temperature resistance of coefficient (NTCR) electroceramics. Complex impedance plane and complex electric modulus formalism are employed to determine the inhomogeneous nature of the electroceramics. This reveals the presence of single elements in the equivalent circuit at elevated temperature. Grain effects are more prominent than that of grain boundary effect at elevated temperature in the material matrix. The electrical conductivity increases sharply with rise in temperature at elevated temperature due to the thermally activated cations. Master modulus analysis provided an evidence of nonexponential type conductivity relaxation occurring in the materials at higher temperatures.