Aging characteristics of 0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 single crystals with different crystal orientations

Abstract

In this work, the time and temperature dependence of the piezoelectric and ferroelectric properties of the 0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 (0.7PMN–0.3PT) single crystals were investigated in order to search for an effective method to improve their properties further. The piezoelectric properties of the [001]-, [110]- and [111]-oriented 0.7PMN–0.3PT single crystals exhibit excellent time stability during the 2-month room-temperature aging process. The re-poling process leads to the improvement of piezoelectric constant d 33 for the [001]-, [110]- and [111]-oriented 0.7PMN–0.3PT single crystals, while the values of electromechanical coupling coefficient k t change little. During the thermal aging, the values of the measured d 33, calculated converse piezoelectric constant $$d_{33}^{*}$$ , maximum strain S max% and longitudinal electrostrictive coefficient Q of the [001]-, [110]- and [111]-oriented crystal plates increase gradually before the ferroelectric phase transition temperatures (T FPT, T R–M, T R–O and T R–T) and then decline continuously. The increase in these values before the T FPT is a result of the phase instability. In general, the [001]- and [110]-oriented 0.7PMN–0.3PT single crystals exhibit large piezoelectricity, excellent time stability and relatively high thermal stability between 20 and 80 °C, which is favorable to the piezoelectric applications.