Effect of Rare Earth Oxides on the Microstructure and Microwave Dielectric Properties of CaO-MgO-Nb2Os-TiO2 System Ceramics

La2O3 and SrO-doped CaO-MgO-Nb2O3-TiO2 system ceramics were prepared by solid-state ceramic technique.The microstructure and microwave dielectric properties of CaO-MgO-Nb2O5-TiO2-La2O3 cermics can be adjusted by varying the amount of La^3＋ or Sr^2＋ ions respectively.The replacement of Ca^2＋ by La^3＋ at A-site of the ceramics increases the quality factor Q value（ at 7.6GHz）as well as the temperature coefficient of resonant frequency τf and decreases the dielectric constant εr and the substitution of Sr^2＋ at A-site in this ceramics system exhibits opposite characteristics.The microwave properties of La^3＋,Sr^2＋-doped CaO-MgO-Nb2O5-TiO2 system ceramics depend on the degree of octahedral distortion inside materials.

Effect of rare earth oxides on the microstructure and microwave dielectric properties of CaO?MgO?Nb2O5?TiO2 system ceramics

La₂O₃ and SrO-doped CaO−MgO−Nb₂O₅−TiO₂ system ceramics were prepared by solid-state ceramic technique. The microstructure and microwave dielectric properties of CaO−MgO−Nb₂O₅−TiO₂−La₂O₃ ceramics can be adjusted by varying the amount of La³⁺ or Sr²⁺ ions respectively. The replacement of Ca²⁺ by La³⁺ at A-site of the ceramics increases the quality factor Q value (at 7.6 GHz) as well as the temperature coefficient of resonant frequency τ _f and decreases the dielectric constant ɛ, and the substitution of Sr²⁺ at A-site in this ceramics system exhibits opposite characteristics. The microwave properties of La³⁺, Sr²⁺-doped CaO−MgO−Nb₂O₅−TiO₂ system ceramics depend on the degree of octahedral distortion inside materials. Funded by the National Natural Science Foundation of China (50272044)