Impedance study of V2O5–TeO2–BaO glasses

Five V2O5–TeO2–BaO glasses were studied using ac impedance. The measurements revealed that dc conductivities increase with V2O5 contents. For glasses having the same V2O5 content, the glass containing less BaO content has higher conductivity. The electric modulus was computer simulated using a stretched exponential relaxation function, ϕ(t) = exp[− (t / τ0)1−n]. The coupling parameter, n, is temperature and composition dependent. The variation of coupling parameter is interpreted in terms of Ngai's coupling model. The dielectric constants at high frequency limit are insensitive to the temperature but increase with V2O5 contents. The activation energies obtained from dc conductivity and relaxation time τ0 are about the same. Both decrease with increasing V2O5 contents.