Contrasting aging behavior of as-grown and annealed BaTiO3 single crystals grown by KF-flux technique

Abstract

Based on defect chemistry analysis and the microscopic mechanism of the aging, the difference in the aging behavior of the two kinds of crystal is fully explained. Our result suggests that besides the thermodynamic driving force due to the symmetry-conforming short-range ordering of point defects, kinetic factors the mobility of point defects also play a crucial role in determining whether or not aging appears. Donor doping is an effective way to reduce the aging effect through eliminating mobile oxygen vacancies. © 2007 American Institute of Physics. DOI: 10.1063/1.2790480 Ferroelectric aging is a generally observed phenomenon, and it strongly affects the application of ferroelectric materials.1-3 It manifests itself as a gradual change in physi- cal properties of ferroelectrics with time, such as the appear- ance of a double hysteresis loop,4,5 the decrease in dielectric constant, and piezoelectric constant.3 These aging effects are well studied and are generally ascribed to the existence of acceptor impurity/dopants, which explained either by a boundary effect6 or volume effect.7,8 Recent study revealed that the aging effect is mainly a volume effect because sig- nificant aging has been found even in domain-wall-free samples.9