Ferroelectric lead scandium tantalate from mechanical activation of mixed oxides

Conventional mixed oxide preparation of lead scandium tantalate, PbSc0.5Ta0.5O3 (PST) powder, requires two calcinations steps, the first of which is to form a Wolframite precursor and the resulting PST phase is structurally long-range ordered. In this work, we report the synthesis of perovskite PST via a novel one-step mechanical activation route, which leads to a long-range disordered structure as verified by X-ray diffraction. Sintered PSTs from the mechanically activated powders also retain the long-range disordered perovskite structure up to 1250 °C, while >95% theoretical density was achieved. They exhibit a spontaneous ferroelectric-relaxor transition at 15 °C with a maximum dielectric constant of ∼13,850 and dielectric loss of <0.04.