ABSTRACT
Ferrite compounds have recently attracted significant interest because of their multifunctional properties. This work investigates the optical, magnetic, and dielectric properties of a LiMn0.5Fe2O4 ferrite prepared by a solid-state reaction. Raman spectroscopy analysis substantiated the presence of the 5 active modes representing the vibration of the oxygen anion at both tetrahedral and octahedral sites. The direct optical band gap was estimated to be 3.51 eV, which indicates the semiconductor behavior of the compound. A theoretical modulation of the hysteresis loop was done to confirm the dominance of the ferromagnetic contribution over the antiferromagnetic one. Furthermore, the dielectric permittivity result indicated a colossal value of the order of 103. The dielectric losses are characterized by the Giuntini law to extract the relaxation process, which is hidden by the DC-conductivity process. Our results indicate the potential of LiMn0.5Fe2O4 for applications in multifunctional devices.
ABSTRACT
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 LiMn0.5Fe2O4 sintered at a temperature of 1100 °C. The X-ray powder diffraction analysis reveals the presence of one cubic phase with the Fd3Ìm 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 LiMn0.5Fe2O4 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 LiMn0.5Fe2O4 is a good candidate for detecting infrared radiations and infrared bolometric applications.
