Synthesis and Characterization of the La0.85Ag0.15Mn0.8Fe0.2O3 Ceramic for Some Device Application

Abstract

We present the synthesis (solid-state reaction) and characterization of an iron-modified lanthanum silver manganate ceramic, La_0.85Ag_0.15Mn_0.8Fe_0.2O₃. XRD investigation at room temperature using Rietveld refinement indicates rhombohedral crystal symmetry (#R \(\overline{3}\) c) with a crystallite size of 30 nm. Scanning electron micrographs demonstrate a homogeneous distribution of well-grown grains with defined grain boundaries, which is critical for understanding the conductivity mechanism. The compactness of the grains verifies the creation of a dense sample, which could be one of the factors contributing to the observed physical attributes. The purity and uniform distribution of all constituent elements were confirmed using the energy-dispersive X-ray analysis spectrum and color mapping, respectively. The Maxwell–Wagner polarization effect is observable at low frequencies. The analysis of impedance and modulus plots indicates the existence of a negative temperature coefficient of resistance and a non-Debye relaxation process, respectively. The existence of a thermally activated conduction mechanism in the investigated sample is supported by the analysis of AC conductivity as a function of temperature and frequency. The semiconducting nature is supported by the existence of semicircular arcs in both the Nyquist’s and Cole–Cole plots, suggesting that they would be good candidates for energy storage devices. The presence of NTC thermistor character for temperature sensor applications is suggested by the resistance versus temperature investigation.