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Some physical properties (such as lattice parameter, curie temperature, ac susceptibility) of Mg1-xZnxFe2O4 (where x = 0.3,0.4,0.5,0.6) ferrites have been studied. Magnesium Zinc Ferrites was synthesized by oxalate co-precipitation method at different synthesis temperature and characterized by X-ray diffraction and far IR absorption techniques, scanning Electron microscopy .The lattice parameter were computed. The X-ray diffraction studies reveal the formations of single phase cubic spinel structure.IR absorption bands are observed around 600 cm-1 and 400 cm-1 on the tetrahedral and octahedral sites respectively. Magnetization parameters such as saturation magnetization, and magnetic moment were calculated and the results are discussed with the help of the existing theories. Saturation magnetization was found to be in the range 2 emu/gm to 8.28 emu/gm when the samples were synthesized below 100°C. The variation of A.C. susceptibility with temperature shows the existence of super paramagnetic nature. The Curie temperature was determined from the measurement of the susceptibility verses temperature. The SEM micrograph shows the uniform distribution of the particles, the average size was estimated to be 0. 350 µm.

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Ni-Cu-Zn ferrites with general formula Ni0.5Cux/2Zn0.5-x/2Fe2O4 (with x = 0.3, 0.4, 0.5 and 0.6) have been synthesized using oxalate precursor method with different precursor reaction temperatures in the range 100C to 700C. The structural analysis has been carried out using X-ray diffraction studies which reveal the formation of ferrites structure. The lattice parameters obtained using the most intense 311 peak are found to be in the range 8.37 to 8.42 Å for all the samples. The saturation magnetization is found to be in the range 20 to 51 emu/g, while the magnetic moment is found to be in the range 0.63 to 1.5 µB. The magnetic losses were found to be maximum for the samples obtained at precursor reaction temperature of 350C. The grain size is found to be in the range 0.4 to 2.0 µm. There is variation in the magnetic properties for different precursor temperatures indicating the effect of reaction history on the various parameters studied.

Lithium ferrites have attracted considerable attention because they have been used as replacements for garnets due to their low cost. A series of polycrystalline ferrite samples with the composition of Li x Zn 0.6−2x Cu 0.4 Fe 2 O 4 (x = 0.05, 0.1, 0.15, 0.2, 0.25, 0.3) at different chemical reaction temperature (100˚C, 125˚C and 150˚C) were prepared using non-conventional microwave sintering method. The characterization was carried out using X-rays technique. The X-ray analysis confirms the formation of single phase cubic structure. The lattice parameter ranges from 8.3690 Å to 8.4653 Å. The X-ray density shows the variation as a function of temperature of synthesis. The variation of AC susceptibility with temperature shows the existence of single domain structure for x ≥ 0.2 when the chemical reaction carried at 125˚C and 150˚C and exhibits super paramagnetic structure for all the composition prepared at 100˚C. The samples x ≤ 0.2 shows multidomain structure for all the samples prepared at 125˚C and 150˚C. The Curie temperature obtained using the susceptibility data are found to be in the range 350˚C to 700˚C. An attempt has been made to synthesis the nanoparticles at lower reaction temperature by using non-conventional microwave sintering method.