Microstructural Characterization and Dielectric Properties of Barium Titanate Solid Solutions with Donor Dopants

Microstructural Characterization and Dielectric Properties of Barium Titanate Solid Solutions with Donor Dopants

The correlation between the sintering temperature and dielectric properties in the $Nb^{5+}\;and\;Ta^{5+}$ doped BaTi$O_3$ solid solutions have been investigated. The samples were sintered at temperatures ranging from 1250 to 1350 ${^{\circ}C}$ for 4 h in air. SEM, XRD and SEM/EDS techniques were used to examine the structure of the samples with particular focus on the incorporation of $Nb^{5+}\;and\;Ta^{5+}$ ions into the BaTi$O_3$ crystal lattice. The X-ray diffraction peaks of (111), (200) and (002) planes of BaTi$O_3$ solid solution doped with different fractions of $Nb^{5+}\;and\;Ta^{5+}$ were investigated. The dielectric properties were analyzed and the relationship between the properties and structure of doped BaTi$O_3$ was established. The fine-grain and high density of the doped BaTi$O_3$ ceramics resulted in excellent dielectric properties. The dielectric properties of this solid solutions were improved by adding a small amount of dopants. The transition temperature of the 1.0 mole% $Ta^{5+}$ doped BaTi$O_3$ solid solution was $\sim$110 ${^{\circ}C}$ with a dielectric constant of 3000 at room temperature. At temperatures above the Curie temperatures, the dielectric constant followed the Curie-Weiss law.