Piezoelectric response and origin in (001) Pb(Mg1/3Nb2/3)0.70Ti0.30O3 crystal

Converse and direct piezoelectric coefficients (d33C and d33D) of (001)-cut Pb(Mg1/3Nb2/3)0.70Ti0.30O3 (PMN-30%PT) single crystals have been investigated as a function of poling electric (E) field. E-field-dependent domain structures were observed by using a polarizing microscope. Both d33C and d33D exhibit a rapid increase at E=1–2 kV/cm and reach maxima at E=2.5–4 kV/cm. This study suggests that polarization rotation from rhombohedral to monoclinic MA phases plays an important role while the high piezoelectric response builds up. Overpoling phenomenon evidenced by a sudden reduction in piezoelectric coefficient with increasing field is very sensitive to Ti content.