Effect of Codoping on the Electrical Properties of Magnesium- and Copper-Containing Bismuth Niobate with Pyrochlore-Type Structure

Bismuth niobate Bi 1.5 Cu 0.375 Mg 0.375 Nb 1.45 Ru 0.05 O 7‒δ with the pyrochlore structure co-doped with ruthenium was obtained by Pechini method. The distribution of Ru 4+ over Nb 5+ sites was established by structural analysis. According to the data of optical reflectance spectra, the optical band gap decreases from 2.40 to 2.27 eV for the sample doped with ruthenium. A small amount of ruthenium in the system was found to result in an increase in conductivity by 0.5 orders of magnitude compared to Cu-Mg–substituted bismuth niobate, due to an increase in the electronic component of the conductivity.