A differential anomalous X-ray scattering study of the formation of lead zirconate titanate via sol-gel process

A differential anomalous X-ray scattering (DAS) investigation on gels, produced by hydrolysis of a mixture of lead(II)acetate and zirconium- and titanium-n-propoxides, and calcinated at the temperatures 200, 300, and 450 degrees C, is presented. Anomalous X-ray scattering was applied to get more precise information on the structural changes of the gel during calcination. Two different scattering experiments for each sample were performed with synchroton radiation of the energy below the L-3 edge of lead, namely at 11500 and 13025 eV. The data were corrected for absorption, fluorescence radiation and multiple scattering. The Compton and atomic scattering were subtracted after normalization to absolute units with values for the anomalous dispersion corrections, determined by an absorption experiment. The Fourier transform of the total and differential scattering intensities yields the total and differential atom pair correlation functions (TAPCF, DACPF), which provide information on the focal structure of lead and its changes during the calcination process. The analysis of the TAPCF's and DAPCF's indicates a structure, similar to that existing in the pyrochlore or perovskite phase of lead zirconate titanate (PZT), even at low temperatures. By comparison of the corresponding atom pair correlation functions (APCF's) it can be deduced that the near range as well as the long range order in the local environment of lead nearly remains unaltered during the calcination process.