Interpretation of electrical conduction mechanism by Godet's VRH model in TiO2 incorporated MnCo2O4 host matrix

摘要

TiO2 incorporated MnCo2O4 host matrix has been investigated for its electrical properties with an objective to get an insight about electrical conduction mechanism in such samples. This unique material has been synthesized using a combination of chemical and physical method. Host spinel was prepared through chemical method and mechanical milling was used to incorporate the dopant. To explore successful substitution of TiO2 in MnCo2O4, XPS analysis was done. Structural, microstructural and compositional characterization has been carried out using XRD, TEM, EDX, and PL. XRD confirms pure cubic phase of nanocrystalline material. Rietveld analysis was appointed to estimate the structural parameters such as lattice parameters, microstrain and crystallite size etc. Impedance analysis shows maximum conductivity for 10% TiO2 incorporated MnCo2O4, beyond which there is a decrease in conductivity. Real part of dielectric constant is also maximum for this particular level of incorporation. The results indicates that Ti ions acts as donor states to increase conductivity. Beyond this particular level of incorporation, the Ti ions goes to grain boundaries and increases the sample resistance. Nyquist plot shows resistance behaviour of the samples and conductivity mechanism has been explained by Godet variable range hopping theory. (C) 2019 Elsevier B.V. All rights reserved.