Dynamical domain observation in relaxor ferroelectrics

Domain reversal in relaxor ferroelectrics (1-x)Pb(Zn_1/3Nb_2/3)O₃ -xPbTiO₃ was observed using a high-resolution CCD (charge coupled device) sensor. This solid solution reveals that the phase transition diffuseness of pure lead zinc niobate decreases with increasing x. Single crystals with x > 0.11 (tetragonal phase) exhibit large sharp domains, and under an electric field domain walls move almost independently of each other. On the other hand, crystals with x < 0.05 (rhombohedral phase) show small ambiguous spindle-like domains, and the domain reversal occurs simultaneously in a certain size region so that each microdomain should change synchronously like cooperative phenomena. Crystals with 0.05 < x < 0.11 exhibit combination domain structures or the intermediate configurations of the above-mentioned two ranges, which correspond to the coexistence of the tetragonal and rhombohedral phases near the morphotropic phase boundary.