Processing, piezoelectric and ferroelectric properties of (x)BiFeO3-(1-x) SrTiO3 ceramics

In this work, BiFeO3-SrTiO3 (BFO-STO) solid solutions have been studied with particular emphasis on the problems related to conventional solid state synthesis of BFO-based systems. This method results in the formation of Bi-rich phase on grain boundaries and inhomogeneities inside the grains, similar to the core-shell microstructure previously reported for several BFO-based ceramic systems. Highly homogeneous and dense BFO-STO ceramics were prepared by mechanochemical activation-assisted synthesis. The as-prepared (x)BFO-(1-x) STO ceramics with 0.7 >= x >= 0.575 exhibited high remanent polarization (30-50 mu C cm(-2)) and a maximum d(33) value of 69 pCN(-1) at x = 0.625. It is shown that the compositions in the close proximity of the pseudocubic phase (x <= 0.6), however, exhibit pronounced aging of d(33) coefficient with time, which is most probably related to the low stability of the domain structure after poling. The results of this study could further promote the processing optimization and compositional design of the BFO-STO and other BFO-based systems.