OBSERVATION OF THE DOMAIN MOTION IN FERROELECTRIC SINGLE-CRYSTALS WITH A DIFFUSE PHASE-TRANSITION

Optical or electron microscopes have been used to observe ferroelectric domains, but they have some difficulties in applying an external electric field or changing the temperature, of a sample. A CCD microscope has been developed for domain observation by combining a low magnification object lens and a high resolution CCD sensor. The CCD microscope has a more than × 1000 magnification on a CRT display. It is easy to apply an electric field on the sample because of a sufficient distance between the lens and the sample. The image of the domain motion is instantaneously recorded with a VTR. Single crystals of the (1 - x)Pb(Zn1/3Nb2/3) O3-xPbTiO3 system prepared by the flux method were used. This solid solution system exhibits a morphotropic phase boundary between rhombohedral and tetragonal phase near x = 0.1. The transition behavior from ferroelectric to paraelectric phase becomes sharp with increasing PbTiO3 concentration (x) in comparison with a diffused phase transition in Pb(Zn1/3Nb2/3)O3. Observation demonstrated that the ferroelectric domain motion is closely correlated with the phase transition diffuseness and dielectric relaxation.