Microwave Dielectric Properties of Bi-Added Ba4Nd9+1/3Ti18O54 Solid Solutions

We have investigated the formation and microwave dielectric properties of the tungstenbronze-type like solid solutions, that is, Bi ions dissolved in Ba6-3x Nd8+2x Ti18O54 solid solution with x=2/3. According to the increase of y in the Ba4(Nd1-y Bi y )9+1/3Ti18O54 compositions, the change of the lattice parameters has an inflection point at y=0.05. Bi was substituted into A2 sites for Ba up to y=0.05 and into A1 sites for Nd over y=0.05. As y increased, the dielectric constant, ε r , increased and the quality factor, Q·f, decreased. The temperature coefficients of the resonant frequency, τ f , improved to 17 ppm/°C at y=0.15. The relationship between the lattice parameters and the microwave dielectric properties of the Bi-added Ba4Nd9+1/3Ti18O54 solid solutions is also presented.