Temperature dependence of piezoelectric properties of high-TC Bi(Mg1/2Ti1/2)O3–PbTiO3

The temperature dependence of both polarization and electric-field induced strain was investigated for (1−x)Bi(Mg1/2Ti1/2)O3–xPbTiO3 (x=0.36, 0.37, and 0.38), with the morphotropic phase boundary located at x=0.37. Remanent polarization (Pr) and maximum polarization (Pmax) of all compositions are enhanced with increasing temperature up to 175 °C, which is rationalized as improved domain switching due to reduced tetragonality (c/a). The hysteresis during unipolar electric cycling tends to decrease with increase in the fraction of tetragonal phase. Temperature dependent x-ray diffraction demonstrates that switched non-180° domains are stable against thermal depoling above 200 °C, which indicates that the currently investigated materials are suitable for high temperature applications. This promising high-TC piezoelectric is further discussed with reference to oxygen octahedron of the tilted R3c and untilted R3m space groups and the tolerance factor (t).