Synthesis and dielectric properties development of new thermal stable bismuth pyrochlores Original Research Article

Structure and dielectric properties of pyrochlore solid solutions in the Bi2O3–ZnO–Nb2O5–Sb2O3 (BZNS) system were investigated. The X-ray diffraction technique was used to analyze the phase structure. Also, the atomic valence of Sb in BZNS pyrochlores was confirmed as quinquevalent cation (Sb5+) by X-ray photoelectron spectroscopy. Sb replacing Nb in the series (Bi1.8Zn0.2)(Zn0.6Nb1.4−xSbx)O7 leads to lower dielectric constant. With increasing amount of Sb5− ions substitution (0≤x≤1.4), the dielectric constant (ε) decreases linearly from 100 to 35 associated with a very low loss The temperature dependence of dielectric constant varies systematically with x. The ceramics with a temperature coefficient of dielectric constant (αε) less than ±15 ppm/°C are reported. The data suggest that the B-site cations play an important role in the determination of dielectric properties for the compounds.