Nanocrystalline ferroelectric phases from mechanical activation of oxide compositions

Abstract

Successful synthesis of nanocrystalline perovskite lead scandium tantalate, PbSc0.5Ta0.5O3, was achieved via a novel one-step mechanical activation route. The as-formed PST exhibits a disordered structure and nanocrystalline domains of ∼8nm. Sintered ceramics made from these powders retain long-range disordered perovskite structure up to 1200°C and a dielectric constant of ∼23,000 is obtained. Sintering above this temperature results in the formation of undesirable pyrochlore phases that degrades dielectric properties.