Effect of sintering temperature on spark plasma sintered PbZr0.52Ti0.48O3: Impedance and energy storage analysis

Abstract

In the present work, the phase analysis, different relaxation mechanisms, dominant conduction mechanism and energy storage performance of spark plasma sintered PbZr0.52Ti0.48O3 (PZT) material at different temperatures (800, 850, 900, and 950 °C) are presented. The XRD analysis indicates difference in phase constitution of the synthesized PZT ceramics in which the sample sintered at 900 °C and 950 °C showed presence of multiple phases. Impedance and electric modulus studies are conducted on the samples over the frequency range 0.01 Hz–1 MHz at room temperature. The analysis revealed approximated Debye type behaviour for low frequency relaxation process in all the samples. The separation of grain and grain boundary relaxation process are observed in the frequency dependent imaginary electrical modulus M″ plots and complex modulus spectra rather than in Bode plots and Nyquist plots. Such contrast was attributed to high resistance and low capacitance of the bulk contribution. Complex impedance measurements, thereby estimating ac conductivity and electric modulus have established a distinctive feature for the PZT spark plasma sintered at 900 °C. The resultant electrical properties of the materials are analyzed through understanding the grain and grain boundary relaxation mechanisms and drawing a possible connection with crystal structures of the sintered materials. PZT sintered at 900 °C, as compared to other counterparts, has shown unique combination of tetragonal and monoclinic crystal structures of constituent phases which exhibits highest impedance and electrical modulus among the samples. The resistances of grain and grain boundary of sample sintered at 900 °C are found to be 1.06 × 105 Ω and 5.80 × 108 Ω respectively. The saturation polarization 17.32 μC/cm2 and the coercive field 5.92 kV/cm of the sample are also found highest and lowest respectively for the 900 °C sintered sample among all the samples studied. The energy storage efficiency of the PZT sintered at 900 °C is also highest ~66.38%.