Characterization of the Dielectric Parameters of Monophase Polycrystalline Bismuth Titanate Pyrochlore (Bi2Ti2O7) Ceramics and Glass-Ceramics

Pyrochlore compounds have a number of technological applications, such as dielectrics for high-frequency and magnetoelectric devices. In bulk materials, they exhibit stimulated cation arrangement and good long-distance order within the pyrochlore framework. Bismuth titanate ceramics containing SiO2 and Nd2O3 were synthesized in the Bi2O3-TiO2-SiO2-Nd2O3 system using the melt-quenching method. In a previous study, the phase composition of selected samples was determined by X-ray diffraction (XRD) analysis and the microstructure was studied by scanning electron microscopy (SEM). The preparation of monophase polycrystalline materials was concluded. Infrared Fourier-transformed spectroscopy (FTIR) was applied in order to identify the structure. The electrical conductivity, as well as the dielectric losses and dielectric constants of selected samples were determined, and the influence of the phase composition on the dielectric characteristics was evaluated. The combination of the pyrochlore phase with the amorphous phase represented by the structural groups Bi-O-Si and Si-O-Si exerts a grain boundary strengthening effect.