Transport phenomena and conductivity mechanism in Sm doped Bi4V2−xSmxO11 ceramics

The polycrystalline samples of Sm doped Bi4V2−xSmxO11 with x = 0.05, 0.10, 0.15 and 0.20 ceramics were prepared by using solid-state reaction technique. The structural characterization of the prepared samples were confirmed by X-ray powder diffraction (XRD) and showed an orthorhombic and monoclinic phase. The nature of Nyquist plot confirms the presence of both grain and grain boundary effects for all Sm doped compounds. The grain resistance decreases with rise in temperature for all the samples and exhibits a typical negative temperature co-efficient of resistance (NTCR) behavior. The ac conductivity spectrum obeys Jonscher's universal power law. The modulus analysis suggests a possible hopping mechanism for electrical transport processes of the materials. The nature of variation of dc conductivity suggests the Arrhenius type of electrical conductivity for all the samples.