Electronic-Ionic Conductivity in Molybdenum Oxide glasses Doped with Sodium ions

摘要

The conductivity of three glasses samples in 30Na2O-(70-x)MoO3-xP2O5 systems and two glass samples in 60%Na2O-40%P2O5 and 60% MoO3-40%P2O5 systems was investigated as a function of temperature. It is also found that conductivity for glasses containing higher percentage of sodium ions is predominantly ionic and in glasses containing higher percentage of molybdenum ions is predominantly electronic. For pure sodium phosphate glass or the glass containing lower concentration of molybdenum the plot of logσ_(dc) vs. 1000/T is almost linear, whereas for glasses containing increasing concentration of molybdenum ions the plots depart front linearity. These'mon-.linear plots indicate a change in activation energy which suggests a contribution from electronic conduction. Ionic glasses exhibit only one conduction process and single activation energy in the whole temperature range. In transition metal oxide glasses with mobile cations, different conduction processes contribute to electronic conduction at different temperature ranges leading.to different values of activation energy. Choosing proper doping levels allows one to tailor mixed conducting oxides.