Effects of heating schedule and atmosphere on the phase formation of plzt thin films prepared using sol-gel process

Abstract

Lead lanthanum zirconate titanate [PLZT(91/651/35)] thin films were fabricated by spin coating of the metallo-organic solutions onto ITO-coated Corning 7059 glass substrates and heat treated at 600[ddot]C for 2 hours with different heating schedules. Microstructure and perovskite phase content of the PLZT thin films were studied using X-ray diffraction analysis (XRD), optical microscope (OM) and scanning electron microscope (SEM). A typical microstructure of the PLZT(91/651/35) thin films prepared using sol-gel process consists of micrometer-scale (about 4–5 μm) circular perovskite grains surrounded nanometer-scale pyrochlore grains. Effects of heating schedule and atmosphere on the crystallization kinetics of the amorphous PLZT thin films were studied. Firing at higher heating rate increased the number of perovskite nuclei and decreased pyrochlore content in the films. Also, the film heat treated at higher heating rate had lower transmittance at visible light because the interface boundary and the grain boundary increased and acted as the light scattering source. The films heat treated in air and O₂ atmosphere have relatively higher perovskite phase content than the film heat treated in Pb atmosphere.

Keywords:

• PLZT
• heating schedule
• perovskite
• pyrochlore