Effect of Sintering Temperature on Structural and Magnetic Properties of Ni0.55Zn0.45Fe2O4 Ferrites

The effect of frequency and sintering temperature on initial permeability of Ni0.55Zn0.45Fe2O4 ferrites have been studied by using an impedance analyzer. The samples were prepared by conventional double sintering ceramic technique using oxide nanoparticles of grain size 30 50 nm. Single phase spinal structure has been confirmed for the prepared samples by X-ray diffraction. As the sintering temperatures increase from 1160 ̊C to 1300 ̊C, the permeability gradually increases. The increase of permeability is ascribed to the increase of density and grain size. Grain size is expected to grow with the increase of sintering temperature. Ferrites with large average grain size posses higher initial permeability. The Curie temperatures determined from temperature dependence of permeability of the samples sintered at different temperatures are found to be Tc = (321 ± 1) ̊C and independent of sintering temperature. At Ts = 1300 ̊C, Tc is found to increase substantially which can be explained by the fact that Zn has evaporated from the surface layer.