CRYSTALLIZATION PROCESSES FROM AMORPHOUS PBTIO3 POWDERS PREPARED BY THE SOL-GEL METHOD

Lead titanate powders obtained by a soi-gel technique have been heat-treated to study the phase transformations from the amorphous to the crystalline state. The process has been investigated by differential thermal analysis, X-ray diffraction and Raman spectroscopy. The sample treated at approximate to 600 degrees C yields the diffraction pattern of a prevalent cubic pyrochlore phase Pb2Ti2O7-x, together with a minority tetragonal perovskite phase, and the former's Raman spectrum is reported. The metastable paraelectric pyrochlore has only previously been observed in thin films. For heat treatments at higher temperatures, only the ferroelectric perovskite is formed.