Phase development in sol-gel derived lead titanate: A XAS study

PbTiO3 powders have been obtained by the sol-gel method using different precursors and catalysts. The whole gelation and crystallisation process was studied by means of XAS spectroscopy at the Ti K-edge and at the Pb L-III-edge. The XANES spectra on the Ti K-edge indicate a marked change of the local environment at 500 degrees C. The local structure around the Ti atoms determined by EXAFS is similar to that observed in the pyrochlore phase for annealing temperatures below 500 degrees C. At this temperature both Ti and Pb environments show the occurrence of the Pb-O-Ti bonds indicating the onset of the transformation to the perovskite phase.