Structural and electrical properties of Zr modified Pb5Ge3O11 ferroelectrics

The polycrystalline sample of zirconium modified lead germanate, Pb5Ge2.5Zr0.5O11 (PGZO), has been synthesized by conventional solid-state reaction technique. The formation of single phase (trigonal) compound was checked with the preliminary structural analysis using X-ray diffraction technique (XRD). Derailed studies of dielectric properties of the PGZO solid solution showed that the ceramic has low dielectric constant (epsilon) and loss (tan delta). Dielectric measurements at different frequencies showed an anomaly at 168 degrees C. From the plots of conductivity (In sigma) vs. inverse of absolute temperature (T-1) the activation energy was calculated. Measurements of polarization and pyroelectric coefficients as a function of temperature suggest that the ferroelectric phase transition in this compound is of second order.