Domain configuration changes under electric field-induced antiferroelectric-ferroelectric phase transitions in NaNbO3-based ceramics

Abstract

We recently developed a feasible crystal chemistry strategy to stabilize the antiferroelectricity in NaNbO3 through a chemical substitution to decrease the tolerance factor and increase the average electronegativity of the system [Shimizu et al., Dalton Trans. 44, 10763 (2015) and Guo et al., J. Appl. Phys. 117, 214103 (2015)]. Two novel lead-free antiferroelectric (AFE) solid solutions, (1-x)NaNbO3-xCaZrO3 and (1-x)NaNbO3-xSrZrO3, have been found to exhibit the double polarization hysteresis typical of a reversible AFE ↔ ferroelectric (FE) phase transition. In this study, as demonstrated by (1-x)NaNbO3-xCaZrO3 system, the influence of chemical modification and electrical poling on the AFE/FE phase stability was investigated, primarily focusing on the microstructural and crystallographic evolutions. Together with the macroscopic polarization hysteresis measurements, a well-demonstrated structure-property relationship was presented. It was found that the CaZrO3 substitution into NaNbO3 can effectively destabilize the FE Q phase and correspondingly lead to a spontaneous reverting to AFE P phase. In contrast to the reversible AFE ↔ FE phase transition, the domain morphology evolution exhibits irreversible nature with a growing process of the orientational domains after applying electric field. Moreover, a multiple-zone axes electron diffraction map of P and Q phases has been summarized and is believed to be an efficient diagram to determine the AFE/FE nature of the NaNbO3-based systems.