Domain pattern variations with temperature were studied by polarizing light microscopy for the morphotropic phase boundary composition $0.67\mathrm{Pb}(\mathrm{M}{\mathrm{g}}_{1/3}\mathrm{N}{\mathrm{b}}_{2/3}){\mathrm{O}}_3-0.33\mathrm{PbTi}{\mathrm{O}}_3$ (PMN-0.33PT) single crystal. At room temperature, the monoclinic ${\mathrm{M}}_{\mathrm{A}}$ phase is the dominant phase in the unpoled crystal, which coexists with a small fraction of the tetragonal (T) phase. The orientation of spontaneous polarization was calculated to be $\sim 4.8^{\circ }$ away from the pseudocubic ${\langle 111\rangle }_C$ in the ${\left\{001\right\}}_C$ plane family. Under an electric field of 6 kV/cm along ${\left[011\right]}_C$, a single domain orthorhombic (O) phase was induced but partially switched back to ${\mathrm{M}}_{\mathrm{A}}$ a few hours after the removal of the $E$ field. It was found that the temperature induced phase transition sequence of the ${\left[011\right]}_C$ poled PMN-0.33PT single crystal is strongly hysteretic. On heating, the phase transition sequence is as follows: coexistence of O phase and ${\mathrm{M}}_{\mathrm{A}}\to \mathrm{rhombohedral}\to \mathrm{monoclinic}{\mathrm{M}}_{\mathrm{C}}\to \mathrm{cubic}\left(\mathrm{C}\right)$. On cooling, the phase transition sequence is given by $\mathrm{C}\to \mathrm{T}\to {\mathrm{M}}_{\mathrm{A}}$. The complete set of dielectric, piezoelectric, and elastic constants for the ${\left[011\right]}_C$ poled PMN-0.33PT single crystal was measured, which showed the strong feature of the single domain O phase with high shear $(d_{15}=2321\mathrm{pC}/\mathrm{N},d_{24}=1941\mathrm{pC}/\mathrm{N})$ and low longitudinal piezoelectric coefficients $(d_{33}=165\mathrm{pC}/\mathrm{N})$.

• Received 7 February 2015
• Revised 12 April 2015

DOI:https://doi.org/10.1103/PhysRevB.91.184105