Microstructural characterization of sol-gel derived Pb1-xLaxTiO3 ferroelectrics

The ferroelectrics Pb1-xLaxTiO3 with good stoichiometry were prepared by a sol-gel route in the composition range from x = 0.0 up to 0.4 in 0.05 increment. The compounds were indexed in a tetragonal phase for 0.0 less than or equal to x less than or equal to 0.25, and in a cubic phase for 0.25 less than or equal to x less than or equal to 0.4. A tiny amount of pyrochlore phase La2Ti2O7 was detected at x = 0.4. The ion oxidation states of solid solution compounds were characterized by X-ray photoelectric spectroscopy (XPS) and electron spin resonance (ESR). For the compounds Pb1-xLaxTiO3 prepared in the atmosphere, the electrical neutrality is kept not by the reduction from Ti4+ to Ti3+, but by the creation of cation vacancies in the A- and B-sites. The grain size of Pb1-xLaxTiO3 increases with increasing La content. (C) 2004 Elsevier B.V. All rights reserved.