Electrical relaxation and grain boundary effect in CdI2 doped glass-nanocomposites

Electrical relaxation in CdI2 doped Ag2O-V2O5-ZnO glass-nanocomposites has been studied using complex modulus formalism. The conductivity formalism has been attempted to explain conductivity spectra due to leaving off of the conductivity in the lower frequency region. This lower frequency conductivity is not distinct due to grain boundary effect. The formation of grain boundary region causes the non-uniform motion of Ag+ in the lower frequency region. Non-Debye type relaxation of Ag+ has been analyzed by invoking Kohlrausch-Williams-Watts function. It is observed that relaxation time (τm) increases up to x = 0.1 and then decreases. Formation of grain boundary and Ag3VO4, Zn2V2O7, Ag4V2O7, CdV2O6 and Cd2V2O7 nanocrystallites play important role in the variation of relaxation time. The stretched exponent (β) values indicate strong ion-ion interaction between mobile Ag+ ions and a strong correlated motion, which makes the relaxation-process non-Debye type.