Studies of pure and doped lead zirconate titanate ceramics and pulsed laser deposited lead zirconate titanate thin films

Abstract

The thesis presents the studies of pure and doped lead zirconate titanate ceramics and pulsed laser deposited lead zirconate titanate thin films. Lead zirconate titanate (PZT) monophase perovskite powder with the composition of Pb(Zr0.52Ti0.48)O3 was prepared via sol gel route. The band gap was calculated for the samples using UV-vis diffused reflectance spectroscopy. The lanthanum doped lead zirconate titanate (PLZT) ceramics with nominal composition Pb1-xLax(Zr0.52Ti0.48)O3 (where x=0, 0.05, 0.10) were synthesized and studied to understand the effect of lanthanum substitution on the dielectric and the ferroelectric properties. The electrical properties of the prepared PLZT ceramics were investigated as a function of frequency for various temperatures using complex impedance spectroscopy (CIS). The values of activation energy of the samples were calculated from the slopes of the Arrhenius plots. The remnant polarization (Pr) and coercive electric field (Ec) were calculated from the ferroelectric hysteresis loop. Perovskite lead zirconate titanate nanostructured (PZT) thin films with Zr/Ti ratio of 52/48 were deposited on Pt/TiO2/SiO2/Si(100) substrate using pulsed laser deposition (PLD) method. For the measurement of ferroelectric property, metal/ferroelectric/metal (MFM) structure with gold as top electrode was used. The results of the ferroelectric properties of the film were illustrated. The voltage dependent Polarization vs. Electric field hysteresis measurements of PZT (52/48) pellet showed a well-defined hysteresis loop with a fairly high remnant polarization (Pr) and low coercive field (Ec). The optical properties of PZT thin film coated on SiO2/Si(100) were investigated using spectroscopic ellipsometry (SE). Spectra of ellipsometric parameters such as and#968; and and#916; were measured as a function of energy at room temperature.