Chemical composition dependence of ferroelectric properties for BaTiO₃–Bi(Mg_1/2Ti_1/2)O₃–BiFeO₃ lead-free piezoelectric ceramics

抄録

The BaTiO₃–Bi(Mg_1/2Ti_1/2)O₃–BiFeO₃ [(1 − x − y)BT-xBMT-yBF] ceramics were prepared by a conventional solid–state synthesis, and their crystal structure and piezoelectric properties were investigated in details. Synchrotron X-ray diffraction (XRD) pattern revealed that a single perovskite phase was obtained for samples at x = 0.050–0.150, y = 0.465–0.735. Splitting of the (111) peak was observed when (x, y) = (0.050, 0.685) and (0.050, 0.735) indicating that crystal structure of samples changed from pseudocubic to rhombohedral phase with increasing BF content. As the BF content increased, the Curie temperature increased. The highest apparent piezoelectric constant d₃₃* values estimated from strain (S) over the applied electric-field (E) value (d₃₃* = S/E) was observed at 300 pm/V for the 0.325BT-0.100BMT-0.575BF ceramics at 25°C and 1 Hz.