Lithium ferrite: The study on magnetic and complex permittivity characteristics

Lithium ferrite (Li0.5Fe2.5O4) powder was prepared by solid state reaction method, which was finally pressed and sintered at 1150 °C. The spinel structure of the lithium ferrite was confirmed by X-ray diffraction and grain size estimation was obtained from scanning electron microscope (SEM). Fourier transform infrared spectroscopy (FTIR) confirmed the presence of primary and secondary absorption bands characteristic for spinel structure. The force constants were estimated using absorption bands for the lithium ferrite. Magnetization and dielectric studies were carried out for the sintered sample. Saturation magnetization (Ms) of 59.6 emu/g was achieved and variation of magnetization with temperature was used to identify the Curie temperature. The complex permittivity (ε∗) for the lithium ferrite sample was obtained for wide frequency range up to 3 GHz and discussed based on available models. The Curie temperature was estimated around 480 °C and verified from both magnetization versus temperature and dielectric constant versus temperature measurements