Nanocrystalline Magnesium ferrite has been prepared by chemical co-precipitation technique. Structural characterization has been performed by X-ray diffraction. Formation of ferrites has also been studied by using FTIR. Frequency dependence of real and imaginary part of initial permeability has been presented for the samples sintered at different temperatures. Real part of initial permeability, increases with the increase of grain growth. The loss component represented by imaginary part of initial permeability decreases with frequency up to the measured frequency of this study of 13 MHz. Curie temperatures have been determined from the temperature dependence of permeability. Curie temperatures for the samples of this composition do not vary significantly with the variation of sintering temperatures. B-H loop measurements have been carried out by B-H loop tracer. Transport property measurements haven been carried out by electrometer and impedance analyzer.

Abstract-The behaviors of the CuFe 2 O 4 nano particle prepared by chemical co-precipitation have been studied. The XRD result of the as dried and samples calcined at different sintering temperature has shown that the single phase has been observed in the as dried condition and there is no observation of extra peak. The grain size has been obtained from Scherrer's formula and found as 4nm to 56nm for the CuFe 2 O 4 nano particle sample with the systematic variation of sintering temperature. Nano particle has been characterized to understand the magnetic properties from the observation of hysteresis loops.The initial permeability varies with sintering temperature due to the variation in kinetics of diffusion which depends on the particle size of the starting material. The Curie temperature has been measured from the result of temperature dependent initial permeability.

Zn substituted Cu-Zn ferrites with a composition Cu 1-x Zn x Fe 2 O 4 have been synthesized by standard double sintering ceramic method and characterized by X-ray diffraction. The single-phase cubic spinel structure of all the samples has been confirmed from X-ray diffraction analyses. The lattice constant is found to increase linearly with the zinc content obeying Vegard's law. This increase in lattice parameter is explained in terms of the sizes of component ions. It is well known that density plays a key role in controlling the properties of polycrystalline ferrites. The X-ray and bulk densities of the Cu-Zn ferrite is significantly decreased whereas porosity increased with increasing Zn concentration, thereby giving an impression that zinc might be helping in the densification of the materials. SEM micrographs exhibit a decrease in grain size with increasing Zn content. The real part of initial permeability, μ ′ increase with increasing Zn contents upto x = 0.5 after that it decreases with higher Zn content.

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In the present work, Cu1-xMgxFe2O4 (x = 0.2, 0.4, 0.6, 0.8 and 1.0) ferrites have been synthesized via a conventional solid-state reaction method. Thermal analysis and the estimation of total weight loss of the samples were performed by differential thermal analysis and thermogravimetric analysis measurements. The thermal variation of initial permeability exhibits unusual dependence with the manifestation of a broad hump followed by a Hopkinson peak attributed to the structural transformation and minimization of magneto-crystalline anisotropy energy, respectively. A decrease in resistivity is observed with increase in temperature and corresponding activation energies for conduction have been calculated. Possible explanations for the observed physical, thermal, magnetic and transport properties with temperature of the samples are discussed in the present paper.