E-field-induced polarization rotation in Pb(Mg1/3Nb2/3)1-xTixO3 crystal

A sequence of field-induced phase transformations was observed by means of a polarizing microscope on a (111)-cut single crystal Pb(Mg1/3Nb2/3)(0.67)Ti0.33O3 at room temperature with an electric field applied along the [111] direction. As electric field increases, polarizations of the rhombohedral R domains whose polar directions are not along [111] rotate first toward a tetragonal T phase associated with 90degrees domain walls. Then the crystal gradually reaches total optical extinction for all polarizer angles at 12 kV/cm, indicating a single [111] rhombohedral R-111 domain with polarization aligned with the electric field. These field-induced phase transformations are irreversible and proceed most likely through M-A-type monoclinic distortions, i.e., R-->M-A-->T-->M-A-->R-111. (C) 2003 American Institute of Physics.