LSNMTix Contribution to the examination of the effect of Ti –substitution on the crystallographic and transport characteristics of

Abstract

A coherent inquiry of the microstructural, structural, hopping transport and dielectric relaxation behaviors in La_0.7Sr_0.25Na_0.05Mn_1-x Ti_xO₃ (LSNMTi_x) (x =0.0-0.2) was carried out to get new comprehension about the impacts of the physical interactions between the titanium and manganese cations on the hopping conductivity and dielectric relaxation features of manganites. LSNMTi_x with x=0.0, and 0.2 are produced based on the ceramic solid-state reaction route. For the investigated compounds, X-ray diffraction data and the Rietveld analysis displayed the occurrence of a rhombohedral single phase with an Rcspace group. Using the SEM images, we found that the ceramics exhibit an average crystal size D_MEB that increases from 193 nm for LSNMTi_0.0 to 230 nm for LSNMTi_0.2. Using the complex impedance and modulus studies, at room temperature, the obtained results revealed the presence of relaxation processes that are ascribed to the main roles of combined grains and grain boundary domains. The compound’s dielectric responses are explicated based on the phenomenological theory of Koop’s and via the model of Maxwell–Wagner. The electrical conductivity spectra are analyzed based on the power law of Jonscher. They confirm that the substitution by the Ti element reduces the electrical conductivity of the prepared system.