Structure, Microstructure, Magnetic and Electrical Properties of Nanostructured Li Ferrite Synthesized by Sol-Gel Process

In this study, Lithium ferrite has been produced by sol-gel method and influence of heat treatment at 1000˚C on its structure and properties has been investigated. Based on X-ray diffraction (XRD) data, it was identified that Li ferrite with cubic crystal structure and P4332 space group is formed successfully before and after heat treatment process. The microstructure of produced powder has been investigated by field emission scanning electron microscope (FESEM). The secondary particles with an average particle size of about 75 nm are observed into initial plate-like clusters. These particles grow to about 10 times larger after heat treatment. Magnetic properties measured by vibrating sample magnetometer (VSM) indicates that the value obtained for saturation magnetization is 53.54 emu/g. After heat treatment, saturation magnetization didn’t change. Magnetic permeability as the most important electromagnetic properties measured in all frequencies showed a significant improvement owing to heat treatment. This improvement is also observed in dielectric constant. Evaluation of magnetic permeability and dielectric constant variation with temperature shows that magnetic and dielectric Curie temperatures are in the range of 830-900˚K and 590-610˚K, respectively.