The effect of synthesis method on the structural, magnetic and electrical properties of nanostructured Li ferrite

In this study, nanocrystalline Li0.5Fe2.5O4 ferrite powders have been prepared by sol-gel, auto-combustion and hydrothermal synthesis methods. The influence of synthesis method on the structure and the properties has been investigated in details. Based on the X-ray diffraction XRD data, the cubic crystal structure with P4332 space group is obtained for Li ferrite produced by sol-gel method, while P4332 space group is observed for the powders prepared by auto-combustion and hydrothermal methods. In addition, a significant amount of impurity is detected for the hydrothermally synthesized powders which is contrary to that observed by two other methods. The microstructure of the produced powder has been investigated by a field emission scanning electron microscope FESEM. A plate-like and spongy morphology with numerous porosity is observed in the Li ferrite powder clusters produced by sol-gel and auto-combustion synthesis methods, respectively. According to the magnetic measurements, the highest saturation magnetization 57 emu/g and the lowest crystallite size 26 nm is detected for the auto-combustion powders. The results also show that dielectric constant and AC electrical conductivity of the auto-combustion Li ferrite is moderately higher that those recorded for the the sol-gel Li ferrite in the all measured frequencies.