Enhancing dielectric and ferroelectric properties of PZT(52/48) electroceramics by niobium doping

Abstract

Finding novel materials and compositions that exhibit a close coupling between ferroelectricity and piezoelectricity is of significant technological importance. Lead zirconate titanate (PZT) is known to benefit from niobium (Nb) doping in a number of ways. In the present study, perovskite Pb(Nb_0.02(Zr_0.52Ti_0.48)_0.98O₃ ceramic material was synthesized and the effect of niobium on the dielectric and ferroelectric properties are investigated. The conventional sol–gel route was used to synthesize Pb(Nb_0.02(Zr_0.52Ti_0.48)_0.98)O₃ ceramics. X-ray diffraction indicates that the perovskite PNZT ceramics exhibit a tetragonal structure free of unwanted pyrochlore phase. In addition to confirming the crystal formation at higher temperatures, simultaneous TGA/DTA analyses of the gel powder reveal endothermic and exothermic peaks that correspond to weight loss at various temperatures. Grain size of the sintered samples was found to be around 300 nm with uniform dispersion, according to SEM examination. The electrical properties of the ceramics were examined as a function of temperature (from room temperature to 500 °C) and frequency (from 100 Hz to 1 MHz) using complex impedance spectroscopy (CIS). The results of the impedance spectrum show that the maximum dielectric constant at Curie temperature is ≈1800 and it reveals that the dielectric loss increases with frequency and the dielectric constant decreases. The sample’s activation energy, which was determined to be 0.167 eV, was calculated using the slope of the Arrhenius plot of DC conductivity vs the inverse of absolute temperature. The coercive electric field (Ec) and remnant polarization (Pr) of the ferroelectric loop evaluated at room temperature were determined to be 3.69 kV/cm and 1.21 μC/cm², respectively.