Structural and microwave dielectric properties of Ba5-xLaxTixNb4-xO15 ceramics

Abstract

The structural and microwave dielectric properties of Ba 5−x La x Ti x Nb 4−x O 15 (1 ≤ x ≤ 3) was investigated. The single phase with A 5 B 4 O 15 -type cation-deficient hexagonal perovskite structure was obtained over the whole composition range. These ceramics have high dielectric constant up to 56, high quality factors (Q×f ) up to 35,000, and low temperature coefficient of resonant frequencies (t f ) in the range +69 to −3 ppm°C −1 . The dielectric constants and t f of these ceramics gradually decrease parallel to an increase in B-site bond valence with increasing La and Ti content.