New quaternary BNT–BT–PMN–PT ceramic: ferro-/piezo-/pyroelectric characterizations

A near morphotropic phase boundary composition of a new quaternary ceramic 0.47(Bi_0.5Na_0.5)TiO₃–0.04BaTiO₃–0.31Pb(Mg_1/3Nb_2/3)O₃–0.18PbTiO₃ [BNT–BT–PMN–PT] has been synthesized using the solid state reaction method. The ceramics were characterized for their ferroelectric properties along with dielectric and piezoelectric characteristics. High value of maximum dielectric permittivity (~ 4140) and transition temperature (T_c ~ 190 °C) with low dielectric loss (< 0.5) were displayed. Well-shaped saturated PE hysteresis loop with high value of remanent polarization (P_r = 13.09 μC/cm²) and coercive field (E_c = 16.56 kV/cm) with excellent fatigue resistance (over 10⁷ cycles) were observed. Together with the conventional P–E hysteresis used for recording the P_r value, which contains false contributions from various polarization artifacts, true remanent hysteresis task was used to unveil the practically usable polarization which was found to be ~ 93% that of the P_r value obtained using conventional hysteresis, suggesting high ferroelectric quality of the quaternary ceramic system. ‘Time-dependent compensated’ ferroelectric loops were traced to analyze the resistive-leakage nature of BNT–BT–PMN–PT system which showed that the system does not show degradation of ferroelectric properties due to change in frequency of applied field. This validates the potential of the material in devices such as actuators where fields are switched at different rates. The ceramic displayed good pyroelectric character in temperature range 95–110 °C. Further, the butterfly loop revealed the piezoelectric coefficient d₃₃^* value to be 177 pm/V. Overall, high T_c, high ferroelectric quality, stability under cyclic electric field and high d₃₃ show that BNT–BT–PMN–PT (with lesser toxicity) is an attractive ceramic for consumer electronic device applications.