Structural, optical, electric and dielectric characterization of a NaCu<sub>0.2</sub>Fe<sub>0.3</sub>Mn<sub>0.5</sub>O<sub>2</sub> compound
Ichrak Ben Slima, Karim Karoui, Abdelfattah Mahmoud, Frèdéric Boschini, Abdallah Ben Rhaiem
Abstract
Hz at various temperatures (333-453 K). The permittivity results prove that there are two types of polarization, dipolar polarization and space charge polarization. The Nyquist diagrams show the contribution of the effects of the grain, grain boundary, and electrode properties. The frequency dependence of the conductivity was interpreted in terms of Jonscher's law. The DC conductivity follows both the Mott and Arrhenius laws at low and high temperature, respectively. The temperature dependence of the power law exponent(s) suggests that the overlapping large polaron tunneling (OLPT) model is the dominant transport process in this material. The optimum hopping length of the polaron (4 Å) is large compared with the interatomic spacing (2.384 Å for Na-O and 2.011 Å for Cu, Fe, Mn-O).