PHASE DEVELOPMENT IN SOL-GEL DERIVED LEAD TITANATE - A XAS STUDY

PbTiO3 powders have been obtained by the sol-gel method using differen t precursors and catalysts. The whole gelation and crystallisation pro cess 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 marke d change of the local environment at 500 degrees C. The local structur e 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.