Microwave dielectric properties of tungstenbronze type like (Ba1−αSrα)6−3xR8+2xTi18O54 (R = Sm, Nd) solid solutions

Tungstenbronze type like Ba6−3xR8+2xTi18O54 (R = Sm or Nd) dielectric ceramics reveal high quality factor Q·f as well as high dielectric constant ɛr. We have investigated the effect of Sr substitution for Ba ions on the microwave dielectric properties of the compounds. (Ba1−αSrα)6−3xR8+2xTi18O54 (R = Sm or Nd) ceramics were prepared in the composition ranges of x = 0–0.2 and α = 0–0.312 and the microwave dielectric properties were investigated. (Ba1−αSrα)6−3xSm8+2xTi18O54, where x = 0.1 and α = 0.298, and (Ba1−αSrα)6−3xNd8+2xTi18O54, where x = 0.2, α = 0.296 revealed remarkably higher Q·f value among the solid solutions, indicating that Q·f increased with substituting Sr ions into Ba ions at the rhombic A1-site. This fact suggests that relaxation of local distortions at the A1-sites is closely related to improvement of Q·f.