AC impedance spectroscopy and conductivity studies of Dy doped Bi4V2O11 ceramics

The ac impedance and conductivity properties ofDy doped Bi(4)V(2) - (x)Dy(x)O(11) (x = 0.05, 0.10, 0.15 and 0.20)ceramics prepared by solid-state reaction technique, in awide frequency range at different temperatures have beenstudied. All the samples exhibited b-type phaseorthorhombic structure at room temperature. The Nyquistplot confirmed the presence of both grain and grainboundary effects for all Dy doped samples. Double relaxationbehavior was also observed. The grain and grainboundary resistance decreases with rise in temperature forall the concentration and exhibits a typical negative temperatureco-efficient of resistance (NTCR) behavior. Ananalysis of the electric modulus suggests the possiblehopping mechanism for electrical transport processes of allthe materials. The ac conductivity spectrum obeys Jonscher’suniversal power law. DC conductivity of thematerials were also studied and values of the activationenergy found to be 0.40, 0.49, 0.73 and 0.78 eV for thecompositions x = 0.05, 0.10, 0.15 and 0.20, respectively,at different temperatures (150–375̊ C).