Microwave Dielectric Properties and Microstructures of RETiNbO6 (RE=La, Sm and Y)

Microwave dielectric ceramics Y(Nb0.5Ti0.5)2O6, SmTiNbO6, LaTiNbO6 have been prepared by conventional solid state method. The single phase of these three kind of samples are obtained at 1350°C, 1340°C and 1280°C, respectively. SmTiNbO6 has positive τf (50.05ppm/°C) and Y(Nb0.5Ti0.5)2O6 (-64.27ppm/°C), LaTiNbO6 have negative τf (-67.39ppm/°C). Dielectric constant, quality factor and temperature coefficient of resonant frequency increase with the increased sintering temperature firstly and then decrease which is due to the lower density. Dense Y(Nb0.5Ti0.5)2O6, SmTiNbO6 ceramics are obtained at the proper sintering temperature but for LaTiNbO6 ceramics there are many pores on the grain surface.