Structural and magnetic properties of nanostructured Li-Ni-Co ferrite prepared by sol-gel method

Li Ni Co ferrite samples with compositional formula Li0.45-0.5xNi0.1COxFe2.45-0.5xO4 with x ranging from 0.00 to 0.1 in steps of 0.02 were prepared by sol gel method. X-ray diffraction (XRD) analysis confirmed the formation of single phase with spinel structure in all the samples. The lattice constant evaluated from XRD data was found to increase with increase of Co2+ substitution and crystallite size was observed in the range of 30-59 nm. The microstructure of the samples was studied by using scanning electron microscopy (SEM). Nanocrystalline nature of ferrites was also confirmed by transmission electron microscopy (TEM). M-H measurements were made using a vibrating sample magnetometer and hysteresis parameters such as saturation magnetization and coercivity were obtained for all compositions. The frequency variations of initial permeability and permeability loss showed a dispersive behavior for all compositions and an increase in initial permeability is observed with increase of Co2+ substitution. The results obtained and mechanisms involved are discussed in the paper.