27 research outputs found

    Plasma-chemical synthesis of Fe3O4 nanoparticles for doping of high-temperature superconductors

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    Abstract Ferrite nanoparticles (Fe3O4) have been produced by the direct low-pressure plasma-chemical synthesis. X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), vibration magnetometry (VSM), and Mössbauer spectroscopy (NGR) were used for measurements, showing that the produced nanoparticles have an average size of 9.4 nm, a crystalline phase of magnetite, possess a property of superparamagnetism at room temperature, and have a blocking temperature of 89 K. The peculiarities of nanoparticle behavior in the magnetic field, related to a large specific surface area, are discussed

    Plasma-chemical synthesis of Fe3O4 nanoparticles for doping of high-temperature superconductors

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    Abstract Ferrite nanoparticles (Fe3O4) have been produced by the direct low-pressure plasma-chemical synthesis. X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), vibration magnetometry (VSM), and Mössbauer spectroscopy (NGR) were used for measurements, showing that the produced nanoparticles have an average size of 9.4 nm, a crystalline phase of magnetite, possess a property of superparamagnetism at room temperature, and have a blocking temperature of 89 K. The peculiarities of nanoparticle behavior in the magnetic field, related to a large specific surface area, are discussed

    The morphological and structural features of ferrite compositions (1-x) MeFe2O4 xP2O5 prepared by plasma spraying

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    Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.Structural features of spinel ferrites formed by rapid quenched from the liquid state, has been studied. It was found that higher quenching rates cause sequential disorder of the spinel structure. Process starts with statistically uniform redistribution of cations at lattice points, then collapse of the anionic frame leads to the topological disorder. This process results in formation of the thermodynamically unstable cluster state and heating of these hardened ferrites leads to a stepwise release of energy. Therefore the described process improves activity of ferrite powders in solid-phase and catalytic reaction

    The morphological and structural features of ferrite compositions (1-x) MeFe2O4 xP2O5 prepared by plasma spraying

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    Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.Structural features of spinel ferrites formed by rapid quenched from the liquid state, has been studied. It was found that higher quenching rates cause sequential disorder of the spinel structure. Process starts with statistically uniform redistribution of cations at lattice points, then collapse of the anionic frame leads to the topological disorder. This process results in formation of the thermodynamically unstable cluster state and heating of these hardened ferrites leads to a stepwise release of energy. Therefore the described process improves activity of ferrite powders in solid-phase and catalytic reaction

    Disentangling invasions in the sea: molecular analysis of a global polychaete species complex (Annelida: Spionidae: Pseudopolydora paucibranchiata)

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