Microwave dielectric properties and Far-infrared spectroscopic analysis of Ba5+nTinNb4O15+3n (0.3 < n < 1.2) ceramics

Ba5+nTinNb4O15+3n ceramics (0.3 < n < 1.2) with a cation deficient hexagonal perovskite related structure were prepared by a conventional solid-state reaction method. The crystal structure and microstructure were investigated by X-ray powder diffraction (XRD) and field emission scanning electron microscope (FE-SEM), respectively. The microwave dielectric properties were measured using a network analyzer. The dielectric constant (ɛr) and the temperature coefficient of resonant frequency (τf) were increased and the quality factor (Q × f) was decreased with increasing in the n value. The effect of the crystal structure on the microwave dielectric properties was also investigated. The FT-IR reflection spectra were obtained and analyzed using a Kramers–Kronig relation.