Effect of Co-doping on the structural and dielectric properties of La${}_{0.8}$K${}_{0.2}$MnO${}_3$ perovskite

In this work, the effect of cobalt ions on the structural and dielectric properties of La${}_{0.8}$K${}_{0.2}$MnO${}_3$ manganite prepared via the simplest sol-gel route is studies. The X-ray diffractions analyses reveal that our perovskites, with the general formula La${}_{0.8}$K${}_{0.2}$Mn${}_{1-x}$Co_xO${}_3$ (x = 0, 0.03, 0.06), crystallized by a rhombohedral structure with R$\overline{3}$c space group. Rietveld refinement indicates that each octahedron (Mn, Co)O${}_6$ has little deformation and that the θ${}_{(Mn,Co)-O-(Mn,Co)}$ bond angles decrease with increasing Co content. From the conductance measurements, it is noticed that the substitution into the Mn site of the LaKMnO${}_3$ material by cobalt increases its conductivity. However, the electrical conductance of our perovskites is well described by the universal Jonscher's law. It is deduced that the conduction process of the present structures occurs between neighboring sites. In addition, the dielectric constant and loss tangent can be explicated based on Maxwell-Wagner polarization. Finally, the Nyquist diagram is fitted by an adequate equivalents circuit, the obtained results depict a non-Debye relaxation process in these materials. (© 2022 Wiley‐VCH GmbH)