The influence of electric poling on structural, thermal, dielectric and ferroelectric properties of Na0.5Bi0.5TiO3 ceramics

摘要

Two types of lead-free Na0.5Bi0.5TiO3 ceramics were manufactured by using a high-temperature solid-state reaction technique. X-ray diffraction analysis showed the formation of a single perovskite phase with the rhombohedral symmetry at room temperature. The structural, vibrational, dielectric and ferroelectric properties of these ceramics in unpoled and poled states were investigated. It was shown that a prior E-field poling process significantly influences the properties of these ceramics. This includes changes in the character of epsilon(T)- and tan delta(T) plots, P(E) hysteresis Mops, as well as shifts of T-d and T-R_T. These effects are mainly attributed to the improvement of polarization/domain ordering and transformation of tetragonal regions into rhombohedral phase by applied electric field. This is accompanied by a change of rhombohedral lattice distortion and a change of unit cell constants. The electric field supported and extended the ferroelectric phase existence towards higher temperatures.