Large Electrostrain from the Ferroelectric Aging Effect around a Morphotropic Phase Boundary

A large electrostrain of ~0.245% emerged in an intrinsic-acceptor-doped morphotropic phase boundary (MPB) system Ba(Ce0.1Ti0.9)O3-x(Ba0.7Ca0.3)TiO3 under an electric field of 30kV/cm at 0.1Hz. It is almost twice as that of hard lead zirconate titanates and larger than the strains of other barium titanate-based systems with either aging effect or MPB effect. This large electrostrain is induced by the coupling of aging effect and MPB effect in the MPB composition. More interestingly, it is found that, different from the aged single phase samples, the aged MPB sample shows a more obvious increase in electrostrain but a slighter decrease in saturation polarization. The explanation for this abnormal aging effect around MPB has been proposed based on the symmetry-conforming principle of point defects. This work demonstrates that the ferroelectric aging effect around MPB could be an effective tool to achieve large electrostrain in ferroelectrics.