Impedance Spectroscopy, Broadband, and Microwave Dielectric Properties of Mechanically Alloyed Ba5Nb4O15 Ceramics

Ba5Nb4O15 (BNO) ceramics were synthesized by the mechanical alloying method. The transmission electron microscope images of BNO powders revealed rod-shaped grains. Mechanically alloyed BNO exhibited maximum density of 97.3% and is explained on the basis of Herring's scaling law. Both the dielectric constant and loss tangent show a stable response up to 0.2 GHz. Further, the dielectric response of BNO ceramics measured above 350 degrees C shows relaxation behavior and is explained using Havriliak-Negami equation. The obtained stable dielectric response of BNO is suitable for type I capacitor and dielectric resonator applications.