High electrical conductivity at room temperature of MnCo2O4 cobaltite spinel prepared by sol–gel method

Abstract

The cobaltite spinel MnCo2O4 nanopowder was prepared by the sol–gel method. X-ray diffraction shows the pure compound that crystallized in the cubic structure with the Fd $$\stackrel{-}{3}$$ m space group. The infrared spectrum (IR) revealed two absorption peaks that can be attributed to Mn–O and Co–O vibrations in the octahedral and tetrahedral sites, respectively. The electrical and dielectric studies were characterized by impedance spectroscopy (IS) at different frequencies (40–106Hz) and temperatures (200–440K). As a matter of fact, the DC conductivity exhibits a semiconductor behavior. It is worth mentioning that the conductivity of our investigated cobaltite spinel was found to be σ = 6.10−3 Sm−1 at room temperature. These results allowed this material to be a good candidate for potential application as an anode material (fuel cell). The AC conductivity obeys the Jonscher's law at low temperatures T 340K. Moreover, the dielectric result shows the permittivity (e '≈ 103) which is due to the contribution of the Maxwell–Wagner polarization.