Sol-gel auto-combustion synthesis of Li3xMnFe2−xO4 and their characterizations

Ferrite samples of Li+ substituted MnFe2O4 nano particles were synthesized by sol-gel auto-combustion method. The samples were obtained by annealing at relatively low temperature at 600 °C and characterized by x-ray diffraction, transmission electron microscopy, vibrating sample magnetometry, and infrared (IR) spectroscopy. Lattice parameter, x-ray density, specific surface area, and porosity are found to increase, whereas bulk density and crystallite size showed the decreasing trend with the Li+ content. Splitting of major absorption bands related to Li+ substituted ferrites were observed in IR spectra. Substitution of Li+ ions for Fe3+ caused a decrease in the saturation magnetization from 75.69 to 58.57 emu/g and the coercivity increased from 157 to 308 Oe. DC resistivity decreases with increase in Li+ content. The temperature dependent results indicate that the values of dielectric constant (ε′) and loss tangent (ε″) increase with the increase in temperature.