In-situ Observation On Domain Switching Of PLZT Ferroelectric Ceramics Via Raman Spectroscopy

Domain switching under an applied external field is considered as a major cause that leads to deterioration of properties of ferroelectric ceramics. It is both theoretically and practically crucial to investigate the fatigue mechanism of this kind of materials by in-situ observation and measurement of domain switching at micro scale. During the course of this study, an in-situ, nondestructive method and experimental setup for observation of 900 domain switching at micro scale were proposed and established based upon the principle of Raman spectroscopy. Accordingly, a series of measurements on the domain switching in three types of pre-polarized PLZT ceramics under applied electric fields, during electric fatigue and at tips of micro cracks were systematically carried out. The variations in peak intensities of characteristic Raman spectra associated with the identified soft modes with the strength of electric field, the cycle number of electric fatigue and the location distribution around the tips were obtained.It was shown that three types of pre-polarized samples exhibited remarkably different behaviors both in ferroelectric properties and microstructure. When an electric field was applied or an electric fatigue was forced, the magnitude of residual polarization and the peak intensities of characteristic Raman spectra associated with the soft modes decreased with an increase in the strength of electric field or in the cycle number of electric fatigue, in particular, the out-plan polarized specimen displayed the most significant reduction. In addition, the peak intensities of characteristic Raman spectra reduced with an increase in the distance away from the crack tip.