PHASE-TRANSITION IN COMPLEX PLZT CERAMICS

The polycrystalline samples of [Pb0.90+(z/1-z)La-0.10](1-z)[Zr-0.53 Ti 0.47+(z/1-z)](0.975(1-z))O-3 of different compositions (z) have been s ynthesized by sol-gel technique.X-ray diffraction (XRD) studies ct the compounds at room temperature suggest the formation of single phase m aterials with tetragonal structure. Detailed studies of dielectric con stant (epsilon) and loss (tan delta) as a function of frequency (400 H z to 10 kHz) in the temperature range from room temperature to 300 deg rees C at 1 and 10 kHz suggest that the compounds have relaxer behavio ur and undergo ferroelectric phase transition of diffuse type. Transit ion temperature (T-c) and diffusivity (gamma) increase whereas the val ues of epsilon decrese with decreasing Zr/Ti ratio.