Spinel ferrites ferromagnetic

The spinel ferrites were fabricated by solid state reaction technique. Cobalt and Zinc ferrites CoxZnyFe204,(x=0.7,0.3,0.4,0.2 and y=0.3,0.7,0.6,0.8) were prepared by solid state reaction technique. The crystalline structure of the sample was investigated by X-ray diffraction(XRD). All samples show cubic spinel structure. The lattice parameter decreases with increasing cobalt content. Magnetic properties shows that the prepared sample exhibit ferromagnetic behaviour at room temperature. The saturation magnetization increases with increasing cobalt content. Curie temperature... 

Spinel ferrite nanoparticles have been intensively studied in the recent years, because of their typical ferromagnetic properties, low conductivity, high electrochemical stability and catalytic behavior. These materials are widely used in large-scale applications (i) in electric and electronic devices, (ii) in H2O, CO2 and alcohols decomposition and in CO and CH4 oxidation [1, 2]. Several routes are used for the preparation of NiFe204 catalysts such as co-precipitation, hydrothermal, sol gel, combustion [3-6] etc. However, the structural and textural properties of ferrite spinel are strongly influenced by the preparation methodology used in their synthesis and may influence the catalytic activity of these materials when used as catalysts. Hence, the effect of the preparation method on the surface acid-basic properties and therefore on the catalytic activity is a very interesting subject. 

Ferrite. Iron which, in pig iron or steel, has not combined with carbon to form cementite (FeaC). It exists in a, /9, y and 8 forms, which vary in magnetism and ahility to dissolve cementite. Name also applied to compd NaFe02 (called Na ferrite), to ferromagnetic oxides having a definite cryst structure (spinels) and the formula M++Fe ++04 of which the divalent metal may be Fe, Ni, Zn, or Mn. The magnetic props vary accdg to the divalent atom present, and ferrites are now tailored for their desired effect, as Ni-Al ferrite ... 

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