Phase transformations in rapid thermal processed lead zirconate titanate

Abstract

The crystallization kinetics of the pyrochlore to perovskite phase transformation in lead zirconate titanate (PZT) thin films have been analyzed using rapid thermal processing (RTP). Sol-gel PZT thin films, fabricated on platinum electrodes, were annealed at 550 °C to 650 °C with hold times ranging from 1 s to 5 min. Glancing angle x-ray diffraction (XRD) was used for depth profiling to identify the location of phases in the films. Transmission electron microscopy (TEM) provided information on grain structure, nucleation, and growth. The phase information was correlated to the ferroelectric and dielectric properties. The perovskite phase nucleated in the pyrochlore phase throughout the film thickness, and at 650 °C the transformation was complete in 15 s. Fast growing (100) PZT nucleated at the platinum and consumed a small-grained matrix until a columnar structure was obtained. A ramp rate of 100 °C/s was sufficiently fast to prevent transformation during heating and allowed the direct application of an Avrami model for transformation kinetics. An activation energy of 610 kJ/mol was determined.

In situ x-ray diffraction of solution-derived ferroelectric thin films for quantitative phase and texture evolution measurement

“…In fact, most studies to date were performed on samples quenched at different stages during the crystallization process. [8][9][10][11] Thus, there is limited information available on the existence, phase, and texture of the intermediate phases and their relationship to the final perovskite phase.…”

A Comparison of Ferroelectric thin Films Prepared by Sol-Gel, Metalorganic Deposition and Photochemical Methods

“…Both of these have been observed to accompany the thermal decomposition of these precursors. ' 3 ,1 4 The FTIR appears to be consistent with the loss of all carbon containing species from the film and the formation of the amorphous metal oxides.…”

“…This is in contrast to previous reports of the formation of MCO 3 resulting from pyrolysis of the metal 2-ethylhexanoates. '1 4 This difference may be associated with the different process conditions. In this work we heated the samples rapidly on a temperature controlled hot plate while the reference used an oven.…”

Piezoelectric Pressure Sensor Based on Enhanced Thin-Film PZT Diaphragm Containing Nanocrystalline Powders

“…For PZT, this initial pyrochlore does not prevent complete transformation to perovskite, but in other materials such as lead magnesium niobate, a single heat treatment to high temperature is a better route so that the pyrochlore formation can be minimized [46]. The effect of heating rate, including rapid thermal processing [47,48], has been explored. An interesting and unexpected effect of thermal treatment on structure was reported by Chen & Chen [49].…”