No abstract

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.

No abstract

Silica-Coated Magnetite nanoparticles (SMNP) recently gained much attractions in biomedical, environmental, construction and nuclear applications. SMNP can overcome the limitations of bare magnetic iron oxide nanoparticles (MNP) such as agglomeration, dissolution and leaching in aqueous and biological system. Silica coating protects the MNP core as well as provides excellent biocompatibility, chemical and thermal stability with higher adsorption capacity of heavy metals and radionuclides. SMNPs are mostly prepared by Modified Stöber method as the simplest route although surface pretreatment or surface modification is needed to avoid formation of large aggregates. Microemulsion method gives excellent size and shape control but needs large quantity of surfactants and solvents. Sonochemical approach provides faster hydrolysis and can prevent agglomeration without any surface pretreatment. Optimal silica coating thickness can provide uniform particles distribution, enough superparamagnetic properties for easy magnetic separation, chemical and thermal stability. Keeping in mind the wide interest in SMNP, this review is designed to report the important information on synthesis, properties and potential applications of SMNP.