Synthesis of single phase 0.9Pb[(Zn0.6Mg0.4)1/3Nb2/3O3]-0.1PbTiO3 by mechanically activating mixed oxides

Abstract

A novel mechanochemical method has been successfully developed to synthesize nanocrystalline 0.9Pb[(Zn0.6Mg0.4)1/3Nb2/3O3]-0.1PbTiO3 (PZN-PMN-PT) powders, lead zinc niobate-lead magnesium niobate-lead titanate, of perovskite structure from constituent oxides. For the first time, the formation of PZN-PMN-PT perovskite phase from the mixed oxides of PbO, ZnO, MgO, Nb2O5 and TiO2 was triggered by mechanical activation at room temperature, and therefore the multiple phase-forming calcinations at elevated temperatures and the subsequent milling are skipped. The resulting PZN-PMN-PT powder exhibits a high specific surface area of 10.86 m2/g with nanocrystallites of 10-15 nm in size and can be sintered to a density of 97% theoretical at 950°C for 1 h. A maximum dielectric constant of 18 986 and a dielectric loss of 0.018 at the Curie temperature of 103°C were measured for the PZN-PMN-PT at 0.1 kHz when it was sintered at 1100°C for 1 h. A diffuseness parameter of 35 K was estimated, which reflects the microcompositional fluctuation in this relaxor ferroelectric.