Roles of microcracking and phase transition on electric fatigue for [001]-oriented Pb(Mg1/3Nb2/3)O3–PbTiO3 single crystals.

Microstructure and polarization degradation are observed under cyclic electric loadings for [001]-oriented Pb(Mg1/3Nb2/3)O3–PbTiO3 single crystals. Microcracking and phase transition are found to bear effect for polarization degradation. Upon cyclic electric loading with a comparatively low field magnitude, phase transition does not occur but the propagation of microcracks significantly reduces the polarization. When electric loading is cycled under a high field magnitude, the single crystal transforms from a rhombohedral phase to a monoclinic one. Both microcracking and phase transition hinder ferroelectric domain switching and reduce the number of electric dipoles that may switch under cyclic electric field. The phase transition degrades the polarization to a greater degree than the microcracks. The results imply that the polydomain state of a ferroelectric rhombohedral phase enhances the electromechanical properties. [ABSTRACT FROM AUTHOR]