Structure characteristics and valence state study for La1−xKxTiO3 synthesized under high-pressure and high-temperature

By using a high-pressure and high-temperature method, perovskite oxides of the type La1−xKxTiO3 (x = 0.30, 0.35, 0.40, 0.45, 0.50) with mixed valence state were synthesized. This new synthesis route has several advantages. XRD analysis shows a cubic cell for the samples. XPS of the surface and EPR measurements indicate that the Ti ions have a mixed valence of 3+ and 4+ and that A-cation vacancies exist in the samples. As x increases, the amount of Ti3+ ions and A-cation vacancies decreases. The valence state of the Ti ions can be altered by changing both pressure and temperature.