Dielectric studies on Ba5Nb4O15-BaWO4 bulk and thin films

Abstract

In the current thesis work, dielectric resonators (DRs) of Ba5Nb4O15 and BaWO4 ceramics have been prepared using mechanical alloying method and semi - alkoxide precursor (sol - gel) method. The Ba5Nb4O15 - BaWO4 composite have been prepared in the bulk form using the conventional solid - state reaction method. The overall efforts in this study are to enhance the microwave dielectric properties of the bulk samples by improving the microstructure and relative density of this material prepared with the addition of their own nanoparticles prepared by sol - gel process. Successful efforts were made to reduce the sintering temperature without affecting the microwave dielectric properties of the Ba5Nb4O15 and Ba5Nb4O15 - BaWO4 ceramics by supplementing with their own nanoparticles. Furthermore, it is proposed to compare the microwave properties of Ba5Nb4O15 (BNO), BaWO4 (BWO) and Ba5Nb4O15 - BaWO4 (BNO - BWO) in bulk and thin film forms. In addition, we have also investigated their optical and electrical properties, which could not only be useful in various applications but also helps in arriving at a comprehensive picture of the physics of these materials, and the results were compared with the existing literature. In the present study, DRs of BNO, BWO and BNO - BWO composite have been prepared by mechanical alloying and solid state reaction method. The BNO, BWO and BNO - BWO thin films were prepared with RF reactive magnetron sputtering respectively.