Temperature Dependence of Piezoelectric Properties of a High Curie Temperature Pb(In1/2Nb1/2)O3-PbTiO3 Binary System Single Crystal near a Morphotropic Phase Boundary

The temperature dependence of the dielectric and piezoelectric properties of a 0.72Pb(In1/2Nb1/2)O3-0.28PbTiO3 binary system single crystal oriented along the [001] axis near a morphotropic phase boundary was investigated in poled and unpoled states. With poling, the permittivity ε r and the dielectric loss tangent tan δ decrease from 2650 and 0.05 before poling to 800 and 0.01 after poling, respectively. The change in both the ε r and the tan δ at the ferroelectric rhombohedral-to-tetragonal phase transition temperature T fr with temperature are significantly reduced with poling. The electromechanical coupling coefficient in the rectangular bar mode, k 33 ′=77%, for phase-array ultrasonic transducers was obtained using the rhombohedral 0.72Pb(In1/2Nb1/2)O3-0.28PbTiO3 single crystal oriented along the [001] axis. With increasing temperature, the value of k 33 ′ decreases slightly in the rhombohedral phase, shows a slight anomaly around T fr, and then remains almost constant in the tetragonal phase. Even at 200°C, the k 33 ′ value decreases by only 5%. The piezoelectric constant d 33 was 700 p C/N at room temperature.