Electric conductivity of sintered glasses based on systems of oxides of lead, germanium and transition metals of group 6

Electric conductivity of sintered glass comprising the PbO - GeO2 - EO3 systems (where E is Cr, Mo, W) has been studied. The chief factor controlling the magnitude of conductivity is the PbO content. In a double glass comprising 50 mol. % PbO conductivity goes 3 orders up and activation energy is reduced by 0.6 eV as compared to those parameters of glasses comprising only 20 mol % of PbO. At constant PbO/GeO2 ratio and PbO concentration between 40 and 60 mol. %, addition of transition metal oxides (in quantities of 3-12 mol. %) is liable to decrease conductivity and raise activation energy. The effect weakens in the following sequence: W → Mo → Cr. EPR spectra have been used to determine the polyvalent state of molybdenum and chromium ions. It is assumed that the conductivity is of combined ion-electron nature