Synthesis and characterization of lanthanum doped sodium bismuth titanate

Impedance spectroscopic studies on polycrystalline sintered discs of lanthanum doped Na-1/2(La-x Bi1-x)(1/2)TiO3 ceramics with x = 0, 0.1, 0.15 and 0.2, have been carried out in the temperature region ranging from room temperature to 550degreesC and in the frequency range of 100 Hz to 1 MHz. Impedance data is presented in frequency explicit plots and Cole-Cole plots. The relaxation behavior of the charge entities in the above samples is studied as a function of temperature. The structural phase transitions present in the samples showed interesting changes with composition frequency and temperature. An attempt is made to correlate the results obtained to the phase transitions present in the samples.