Investigation of structural, morphological, and transport properties of a multifunctional Li-ferrite compound

The development of multifunctional materials is an exceptional research area, which is aimed at enhancing the versatility of materials in various applications. In this context, the exceptional properties of ferrite materials have attracted the attention of researchers. For this reason, we synthesized LiMn_0.5Fe₂O₄ sintered at a temperature of 1100 °C. The X-ray powder diffraction analysis reveals the presence of one cubic phase with the Fd3̄m space group and confirms the spinel structure formation. Moreover, the elemental analysis by EDX reveals the homogeneous distribution of iron and manganese cations. Scanning electron microscopy shows that the grain size is of the order of 2.48 μm. Impedance spectroscopy was performed in the temperature and frequency ranges from 200 K to 380 K and 40 Hz to 10⁶ Hz, respectively. The Nyquist plots revealed the presence of grains and grain boundary contributions. The semiconductor nature, obtained by the conductivity study, indicates that LiMn_0.5Fe₂O₄ is promising in optoelectronic applications. Dc conductivity is found to be thermally activated with an activation energy of 370 meV, 255 meV, and 199 meV for 200-270 K, 280-330 K, and 340-380 K regions, respectively. From the Jonscher power law, the correlated barrier hopping model (CBH) and non-overlapping small polaron tunneling (NSPT) prevailed in the conduction process. Besides, the temperature coefficient of resistivity (TCR) affirmed that LiMn_0.5Fe₂O₄ is a good candidate for detecting infrared radiations and infrared bolometric applications.