Quantitative WDXS microanalysis of bismuth-based BaBi4Ti4O15 perovskites doped with Nb and Fe

Quantitative electron-probe microanalyses was used to determine the chemical composition of a Fe- and Nb-doped bismuth-based BaBi4Ti4O15 perovskite compound. Elemental concentrations of Fe, Nb, Bi, Ba and Ti were accurately measured using wavelength-dispersive x-ray spectroscopy that was optimized for the analysis of a complex oxide matrix containing minor concentrations of dopants. Measurements were performed with a JEOL JXA 840A electron probe microanalyser at 20 and 26 kV, 50 nA beam current, 100 s maximum counting time and 0.3 % preset counting deviation (σc) using both PET and LiF crystals. K-ratios were quantified by the ZAF and the φ(ρz) PAP matrix-correction procedures. The results showed that dopants incorporate into the BaBi4Ti4O15 at Ti4+ sites according to the Ba1-4XBi4+4X Ti4-4XFe4XO15 and Ba1+4X Bi4-4XTi4-4XNb4XO15 solid-solution formulae. The majority of the excess charge introduced by the substitution of Ti4+ with Fe3+ or Nb5+ is compensated for the change in the Ba2+ /Bi3+ ratio. (author)