Dielectric and energy storage characteristics of 0.2, 0.4, 0.6, 0.8 wt% Cr2O3 doped PbZr0.52Ti0.48O3 ceramics synthesized by spark plasma sintering

Abstract

The microstructure, phase analysis, impedance and modulus spectroscopies, dielectric and energy storage characteristics have been carried out on Cr2O3 doped PbZr0.52Ti0.48O3 (PZT) ceramics. The PbZr0.52Ti0.48O3 + x Cr2O3 (x = 0.2, 0.4, 0.6 and 0.8 wt%) ceramics were synthesized by solid state reaction method following spark plasma sintering technique. The particle size of calcined powders lies between 200 nm and 500 nm, and the particles have largely faceted morphology. The analysis of X-rays diffraction patterns of the ceramics reveals perovskite structure with tetragonal lattice having P4mm space group. No additional peak related to Cr- based compound has been detected, which indicates Cr solubility in the PZT solid solution. The Cr2O3 doped PZT samples exhibit ≥ 99.3 % relative density with average grain size lower than that of undoped PZT samples reported. The peak value of dielectric permittivity (εm) was found to decrease when the Cr2O3 content is above 0.2 wt%; however, it increases for 0.8 wt% Cr2O3 doped sample. Such behavior is explained based on the multivalent nature of chromium ions. The impedance and modulus spectroscopic analyses reveal the contributions of grain relaxation and confirm the non-debye type of relaxation. The modulus studies reveal the presence of hopping mechanism in the material. The DC conductivity curves show a typical Arrhenius type behavior of electrical conductivity. The energy storage studies reveal an increase in remnant polarization and coercive field for samples containing up to 0.6 wt% Cr2O3 and the results are in agreement with the XPS observations. The highest energy storage density (∼0.1 J/cm3) and efficiency (∼64%) under an electric field of 25 kV/cm were observed for 0.2 wt% and 0.8 wt% Cr2O3 doped PZT samples, which are attributed to the dominant presence of donor Cr5+ ion.