Microwave dielectric properties and crystal structure of the tungstenbronze-type like (Ba1 − αSrα)6(Nd1 − βYβ)8Ti18O54 solid solutions

A study of the dielectric properties, especially the Q × f value, of the tungstenbronze-type like (Ba1 − αSrα)6 − 3xNd8 + 2xTi18O54 solid solutions in x = 0 system was carried out. These compositions near x = 0 have very low Q × f values. To improve the Q × f value of these materials, we tried two substitutional systems, which are (Ba1 − αSrα)6Nd8Ti18O54 and Ba4Sr2(Nd1 − βYβ)8Ti18O54. In the former composition, the Q × f value was increased from 206 to 5880 GHz in the range of 0 ≤ α ≤ 0.5. And we found that Sr ions substituted for Ba ions in A1 sites have good effect on increasing the Q × f value, but Sr ions substituted for Ba ions in A2 sites have poor effect on increasing it. The latter composition also has a small effect on increasing the Q × f value.