DOMAIN-RELATED PHASE TRANSITIONLIKE BEHAVIOR IN LEAD-ZINC NIOBATE RELAXOR FERROELECTRIC SINGLE-CRYSTALS

The relaxor ferroelectric lead zinc niobate (Pb(Zn1/3Nb2/3)O-3) has be en intensively investigated, because of its large dielectric and piezo electric properties for applications in actuators and transducers. In this study, the in-situ behavior of the domains in Pb(Zn1/3Nb2/3)O-3 s ingle crystals has been observed using optical microscopy in combinati on with a charge-coupled device (CCD) camera, The temperature of the s ample has been cycled between -185 degrees C and +200 degrees C, while applying an electric field of up to +/-10 kV/cm, Many characteristics , such as the induction of birefringence, the transition between the m icrodomains and macrodomains, and the ''freeze-in'' of the macrodomain s, have been optically observed, The optical and dielectric data hale been collected and plotted as a function of temperature and electric f ield, An electric-field-temperature diagram showing five domain-relate d regions has been proposed, The microdomain-to-macrodomain phase tran sition like behavior seems to be an analog of a martensitic phase tran sition.