Cr-doped lead lanthanum zirconate titanate (PLZT) ceramics for pyroelectric and energy harvesting device applications

Cr-doped PLZT ceramic compositions (Pb0.94La0.06)(Zr0.57Ti0.43)O-3 + X mol% of Cr2O3, (X = 0.00, 0.05, 0.11 and 0.16) prepared by solid state reaction have been characterized for their structural and pyroelectric properties. Rietveld refinement of X-ray diffraction (XRD) data reveals tetragonal structure with space group P4mm, and the tetragonality ratio c/a increases with increasing Cr content. Raman spectroscopy reveals the coexistence of both rhombohedral and tetragonal phases in the system suggesting a polymorphic character providing easy rotation of polarization and improved pyroelectric response. Figures of merit (FOM) useful for device design have been estimated using the measured material properties such as pyroelectric current, density, specific heat, polarization, dielectric constant and loss. A specific Cr2O3 content of X = 0.11 in PLZT is found to exhibit optimum performance characteristics for pyroelectric and thermal energy harvesting applications.