Structural and transport characteristics of substituted bismuth niobates

The results of studying solid solutions with the composition of Bi₃Nb_{1 ? y} Zr _y O_{7 ± δ}, Bi_2.95Y_0.05Nb_{1 ? y} Zr _y O_{7 ± δ} (y = 0–0.5; Δy = 0.1), and Bi_6.95Y_0.05Nb_{2 ? y} Zr _y O_15.5 (y = 0.1–1; Δy = 0.1) are presented. XRD and electron microscopy with X-ray microanalysis are used to determine the homogeneity regions of solid solutions; crystallochemical parameters are calculated. It is shown that irrespective of the ratio of Bi: Nb, two cubic phases are formed at an increase in the dopant amount. One of these represents a solid solution based on Bi₃NbO₇ (δ-phase) and the second one is a solid solution based on δ-Bi₂O₃ (δ′-phase). Conductivity of sintered samples is studied using the impedance spectroscopy technique. Introduction of yttrium into the bismuth sublattice results in no increase in conductivity of solid solutions, while in the case of the ratio of Bi: Nb = 3: 1, overall conductivity of solid solutions is somewhat higher at similar dopant concentrations.