Microstructural characterization of sol–gel derived Pb 1− xLa xTiO 3 ferroelectrics

Abstract

The ferroelectrics Pb 1− x La x TiO 3 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 ≤ x < 0.25, and in a cubic phase for 0.25 ≤ x < 0.4. A tiny amount of pyrochlore phase La 2Ti 2O 7 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 Pb 1− x La x TiO 3 prepared in the atmosphere, the electrical neutrality is kept not by the reduction from Ti 4+ to Ti 3+, but by the creation of cation vacancies in the A- and B-sites. The grain size of Pb 1− x La x TiO 3 increases with increasing La content.