Giant piezoelectric behavior in relaxor ferroelectric environment friendly NaKLiNbTaSbO ceramics for high temperature applications

Lead free NaKLiNbTaSbO (NKLNTS) ferroelectric ceramic was synthesized to replace lead based ceramics with high piezoelectric performance for application in sensors, transducers and other electronic devices. The synthesis of NKLNTS ceramic was carried out using solid state reaction technique and the sintering temperature was taken to be 1090 °C. The structural phase of synthesized ceramic was found to be pure perovskite as observed from powder X-ray diffraction. FE-SEM micrographs revealed the formation of homogeneous microstructure with well defined grains. The excellent dielectric response with a high value of Curie temperature (in the range 305–315 °C for all frequencies) and low dielectric loss (0.06 at high frequency of 2 MHz at room temperature) was observed. J–E curve was analyzed and conduction mechanism in NKLNTS ceramic was found to be Ohmic. A ‘Displacement–Voltage’ butterfly loop was traced and a very large value of piezoelectric charge coefficient (d* ~ 754 pm/V) was obtained. P–E hysteresis loops were traced to study ferroelectric behavior of NKLNTS ceramic. The value of pyroelectric coefficient was obtained to be very high ∼ 1921.9 µCm °C. Fatigue test was performed over 10 switching cycles and fatigue free nature of NKLNTS ceramic was observed. Remanent hysteresis task was performed to determine the true-remanent polarization of NKLNTS ceramic. Time-dependent compensated hysteresis task was carried out which revealed resistive leakage free nature of the ceramic.