Effects of partial Li-substitution on structural, electrical and dielectric properties in La1-xLixSrMn2O5+d(x=0.05, 0.10 and 0.15) brownmillerite oxides

In this work we have studied the effects of substitution of lanthanum by Li at the A site on the structural, electrical and dielectric properties of the brownmillerite compounds La1-xLixSrMn2O5 +delta(x = 0.05, 0.10 and 0.15). The samples prepared by the sol-gel reaction method. Structural investigation by RX diffraction shows that all compounds crystallize in the cubic structure with space group Pm-3 m at room temperature. The morphology and grain size of the compounds were observed using a scanning electron microscope (SEM). Impedance spectroscopy is used to study the AC electrical properties of these materials in the temperature range 10 0-20 0 K and in the frequency range 100 Hz to 1 MHz. To study the dielectric behavior of materials and various physical phenomena. Complex impedance plane plots show the grain contribution for the samples. The Nyquist plot Z' as a function of Z at different temperatures shows semicircular arcs describing an equivalent circuit.& nbsp;Variation of the modulus and electrical conductivity of the compound shows conduction phenomena and a no-debye type relaxation process. The electrical conductivity was determined using Jonscher's law and the activation energies were determined from the conductivity and the imaginary part of the impedance. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

This study investigated the effects of lanthanum substitution by Li on the structural, electrical, and dielectric properties of brownmillerite compounds, with a focus on the behavior at different temperatures. Analysis of impedance spectroscopy and Nyquist plots provided insights into the characteristics of the samples at varying temperatures. Overall, the research shed light on the conduction phenomena and relaxation processes in the compounds.