Study of dielectric and impedance spectroscopy of La substituted nanocrystalline Pb(Zr0.52Ti0.48)O3 ceramics

Nanocrystalline Pb1-xLaxZr0.52Ti0.48O3 ceramics with x = 0.00, 0.02, 0.04, 0.06 and 0.1 were prepared by the sol gel method. X-ray diffraction analysis of the calcined powder at room temperature shows mixed rhombohedral and tetragonal crystal structure. The grain size increases with the increase in lanthanum concentration. Dielectric properties of the samples were studied as a function of frequency and temperature. The Curie temperature decreases and dielectric constant increases with the increase in La3+ concentration. The frequency dependent ac conductivity follows Jonscher power law. The detailed study of relaxation process and microstructure effect has been carried out by impedance spectroscopy. The Nyquist plot shows two semicircles ascribed to the grain and grain boundary effect in La3+ substituted PZT ceramics. A non-Debye type relaxation was observed in all the samples.