Dielectric Behavior of Yttrium doped Barium-zirconium-titanate Ceramics

The ferroelectric behavior of the yttrium-doped barium-zirconium-titanate perovskite ceramics Ba1-xY2x/3Ti.75Zr0.25O3 (with x = 0.0, 0.01, 0. 025, 0.05) has been studied. The room temperature X-ray diffraition study suggests that all the compositions have a single-phase cubic symmetry with space group Pm-3m, The temperature dependent dielectric constant of the ceramics was investigated in the frequency range from 50 Hz to 1 MHz. The density of the samples was determined usina Archimedes' principle and was found to be similar to 98% of the X-ray density. A broad dielectric anomaly coupled with a shift of the dielectric maximum towards a higher temperature with increasing frequency indicates relaxor-type behavior in the ceramics With increasing in yttrium content, the Curie temperature decreased, except-for x = 0.01 where the Curie temperature increased. The relative permittivity decreased and broadened with increasing yttrium content.