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Kumar S.,Pandit Anant Ram Sanatan Dharam College | Shinde T.J.,Kusumtai Rajarambapu Patil Kanya Mahavidyalaya | Vasambekar P.N.,Shivaji University | Bhatt K.,Wilson College
IEEE Transactions on Magnetics | Year: 2015

Nanocrystalline ferrites with composition Mn0.2Zn0.8InyFe2-yO4, ( $y = 0.00$ , 0.035, 0.070, 0.100) were prepared by oxalate co-precipitation technique followed by microwave heating of precursors. The phase purity of the samples was confirmed by X-ray diffraction technique. Full profile Rietveld refinement of the powder diffraction pattern was carried out by using General Structure Analysis System II to obtain cation distribution in the spinel lattice. In3+ ions were distributed in tetrahedral as well as octahedral sites. Magnetization of ferrite samples was studied with vibrating sample magnetometer. In lower concentration, indium substitution increased saturation magnetization; at higher concentration of indium, saturation magnetization decreased substantially. This was due to higher fraction of indium ions occupying octahedral sites. AC susceptibility and Loria-Sinha techniques were used to study Curie temperature of nanoferrites. © 1965-2012 IEEE. Source

Kumar S.,Pandit Anant Ram Sanatan Dharam College | Shinde T.J.,KRP Kanya Mahavidyalaya | Vasambekar P.N.,Shivaji University
Journal of Magnetism and Magnetic Materials | Year: 2015

Nanocrystalline Indium substituted Mn-Zn ferrites were prepared by oxalate coprecipitation technique in combination with microwave heating. X-ray diffraction and scanning electron microscopy was used to study nano-structural parameters such as crystallite size, lattice constant, X-ray density, observed density and morphology of the synthesized nanopowders. The lattice constant, crystallite size and X-ray density increased with increase in Indium concentration. Thermal variation of dc resistivity was studied by two probe method. The resistivity decreased exponentially with increasing Indium concentration and the change of slope of dc resistivity plot was observed at Curie temperature. Small polaron hopping between Fe2+ and Fe3+ ions at octahedral sites was established. Substitution of Indium ions increased the dc resistivity. Differential method was used to study thermoelectric power. Thermo-emf remained constant with increasing temperature; the n-type conduction mechanism and localization of charge carriers at lattice sites due to strong electron-phonon interaction was established. © 2014 Elsevier B.V. All rights reserved. Source

Kumar S.,Pandit Anant Ram Sanatan Dharam College | Shinde T.J.,KRP Kanya Mahavidyalaya | Vasambekar P.N.,Shivaji University
AIP Conference Proceedings | Year: 2013

Nanocrystalline spinel Ferrites have excellent magnetic properties that are dependent on chemical composition, the method of preparation, and cation distribution. Nanocrystalline Mn0.8Zn0.2In 0.070Fe1.930O4, were prepared by combination of oxalate co-precipitation technique and microwave heating. X-ray diffraction profile was fitted by Rietveld refinement using GSAS(General structure and analysis system). Room temperature magnetic properties were studied using vibrating sample magnetometer. Cation distribution obtained from Rietveld refinement was used to analyse the magnetic properties of nanocrystalline Ferrites. © 2013 AIP Publishing LLC. Source

Kumar S.,Pandit Anant Ram Sanatan Dharam College | Shinde T.J.,KRP Kanya Mahavidyalaya | Vasambekar P.N.,Shivaji University
Advanced Materials Letters | Year: 2013

Powder diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy were used to characterize the spinel structure of nanocrystalline Ferrites with composition Mn1-xZnxFe2O4 (x = 0.2, 0.4, 0.6 and 0.8) prepared by oxalate coprecipitation technique and followed by microwave heating of precursors. Effect of composition on the lattice constant, x-ray density, crystallite size was studied. Crystallite size and x-ray density increases with increase in Zinc content. The face centered cubic spinel structure has undergone deviation from ideality. A correlation exists between splitting of infrared absorption bands and lowering of composition dependent crystalline symmetry. This preparation technique could be used for synthesis of materials which use microwave transparent precursors. © 2013 VBRI press. Source

Kumar S.,Pandit Anant Ram Sanatan Dharam College | Shinde T.,Kusumtai Rajarambapu Patil Kanya Mahavidyalaya | Vasambekar P.,Shivaji University
International Journal of Applied Ceramic Technology | Year: 2015

Magnetic properties of polycrystalline spinel ferrites are of significant interest in scientific community. Of all, initial permeability is most important magnetic property for device fabrication. Mn-Zn and Ni-Zn ferrites are commercially most successful class of ferrites. Ferrites accommodate variety of cations in interstitial sites; type of cations, their occupancy at interstitial sites, grain size, pores, defects, or other imperfections in ferrites regulate their response to external magnetic stimulus. These factors are influenced by composition and preparation method. The failure of initial permeability of ferrites, to withstand variation in frequency of applied signal has fueled intense efforts in scientific community to optimize frequency stability of permeability. Therefore, improvement in their permeability is important from commercial perspective, and it further enables deeper insight into the dynamical link between microstructure and magnetic properties. This work presents a review of initial permeability in Mn-Zn and Ni-Zn ferrites with a focus on influence of intrinsic factors and frequency of applied signal. The work is an analytical assessment to provide framework for engineering high permeability in ferrites. © 2014 The American Ceramic Society. Source

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