The results of direct- and alternating-current conductivity measurements of BixGe1-xO2-0.5x (x = 0.13, 0.23, 0.33 or 0.47) and BixSi1-xO2-0.5x (x = 0.47, 0.57 or 0.67) glasses were reported and analyzed with the aim of understanding the conduction mechanism. It was suggested that the conductivity could be explained by a single ionic mechanism. An explanation of the marked increase in conductivity for x > 0.33 was proposed on the basis of percolation in a high-mobility BiO5–6 network.

Ionic Conductivity of Bismuth Silicate and Bismuth Germanate Glasses. B.Kusz, K.Trzebiatowski, R.J.Barczynski: Solid State Ionics, 2003, 159[3-4], 293-9