Electrical properties of ion conducting molybdate glasses

Abstract

The electrical conductivity and conductivity relaxation of xAg₂O-(1-x)MoO₃ glasses have been reported in the frequency range of 10 Hz-2 MH_z and temperature range of 183-413 K. The dc conductivity and activation energy for the binary silver molybdate glasses have been compared with those of Ag⁺ ion conducting binary phosphate, borate, and tellurite glasses. The silver molybdate glasses exhibit the highest conductivity and the lowest activation energy of the glasses formed with other glass formers such as phosphate, borate, and tellurite containing the same modifier Ag⁺ ions. We have analyzed the ac conductivity using the power law and the electric modulus formalisms. We have observed that the concentration of mobile Ag⁺ ions is not thermally activated and only 10%-25% of the total Ag⁺ ions contribute to the dynamic processes and are independent of the Ag₂O content. We have observed that the conductivity relaxation is highly nonexponential. The motion of Ag⁺ ions is decoupled more and more from the viscous motion of the glassy matrix with the increase of Ag₂O content in the investigated glass composition.