Fernando Rhen - Academia.edu (original) (raw)
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The study of magnetic nanoparticles has attracted great attention of researchers in nanoscience a... more The study of magnetic nanoparticles has attracted great attention of researchers in nanoscience and nanotechnology. It has been recognized that these systems can be applied in several fields, including catalysis, biomedicine, magnetic resonance imaging, data storage media, and drug delivery among others. We have produced Fe3O4 and CoFe2O4 magnetic nanoparticles (MNP) functionalized with amino acid (L-aspartic acid). The MNP were obtained by the thermal decomposition method using ionic liquid (IL) as solvent. Recycles reactions were conducted at least six times using the IL. X-ray powder diffraction measurements showed that all Bragg reflections belong to either MNP crystal phase or the matrix phase which is the L-aspartic acid. The broad peaks from nanoparticles correspond to spinel cubic symmetry and the amino acid matrix shows intense and narrow peaks belonging to the monoclinic P21a space group. The nanoparticles size and its distribution have been determined by transmission elec...
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2008 Twenty-Third Annual IEEE Applied Power Electronics Conference and Exposition, 2008
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2008 IEEE Power Electronics Specialists Conference, 2008
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2007 IEEE Power Electronics Specialists Conference, 2007
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Journal of Magnetism and Magnetic Materials, 2008
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Journal of Magnetism and Magnetic Materials, 2010
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Journal of Applied Physics, 2000
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Journal of Applied Physics, 2009
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Journal of Applied Physics, 2013
ABSTRACT Here, we present an implementation of the moving Preisach model to describe the magnetic... more ABSTRACT Here, we present an implementation of the moving Preisach model to describe the magnetic behaviour of Sm-Co films. We use two independent Preisach distributions to separate the magnetization into reversible and irreversible components. The numerical simulation works very well for a system where two magnetic phases are weakly or negligibility coupled. We tested our implementation on nanocrystalline Sm-Co films prepared by sputtering and having composition around Sm25Co75. We found that the Sm25Co75 film has a soft and hard phase and quantified their contributions to the total magnetization. Using the moving Preisach model, we characterized the properties of the hard phase, which has a coercivity of 1.26 T and contribution of 74% to the total magnetization. The soft magnetic phase contributes 26% to the total magnetization and has a coercivity of 0.056 T.
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IEEE Transactions on Magnetics, 2000
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IEEE Transactions on Magnetics, 2000
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Electrochimica Acta, 2009
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Electrochemistry Communications, 2008
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The study of magnetic nanoparticles has attracted great attention of researchers in nanoscience a... more The study of magnetic nanoparticles has attracted great attention of researchers in nanoscience and nanotechnology. It has been recognized that these systems can be applied in several fields, including catalysis, biomedicine, magnetic resonance imaging, data storage media, and drug delivery among others. We have produced Fe3O4 and CoFe2O4 magnetic nanoparticles (MNP) functionalized with amino acid (L-aspartic acid). The MNP were obtained by the thermal decomposition method using ionic liquid (IL) as solvent. Recycles reactions were conducted at least six times using the IL. X-ray powder diffraction measurements showed that all Bragg reflections belong to either MNP crystal phase or the matrix phase which is the L-aspartic acid. The broad peaks from nanoparticles correspond to spinel cubic symmetry and the amino acid matrix shows intense and narrow peaks belonging to the monoclinic P21a space group. The nanoparticles size and its distribution have been determined by transmission elec...
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2008 Twenty-Third Annual IEEE Applied Power Electronics Conference and Exposition, 2008
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2008 IEEE Power Electronics Specialists Conference, 2008
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2007 IEEE Power Electronics Specialists Conference, 2007
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Journal of Magnetism and Magnetic Materials, 2008
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Journal of Magnetism and Magnetic Materials, 2010
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Journal of Applied Physics, 2000
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Journal of Applied Physics, 2008
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Journal of Applied Physics, 2009
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Journal of Applied Physics, 2013
ABSTRACT Here, we present an implementation of the moving Preisach model to describe the magnetic... more ABSTRACT Here, we present an implementation of the moving Preisach model to describe the magnetic behaviour of Sm-Co films. We use two independent Preisach distributions to separate the magnetization into reversible and irreversible components. The numerical simulation works very well for a system where two magnetic phases are weakly or negligibility coupled. We tested our implementation on nanocrystalline Sm-Co films prepared by sputtering and having composition around Sm25Co75. We found that the Sm25Co75 film has a soft and hard phase and quantified their contributions to the total magnetization. Using the moving Preisach model, we characterized the properties of the hard phase, which has a coercivity of 1.26 T and contribution of 74% to the total magnetization. The soft magnetic phase contributes 26% to the total magnetization and has a coercivity of 0.056 T.
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IEEE Transactions on Magnetics, 2000
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IEEE Transactions on Magnetics, 2000
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Electrochimica Acta, 2009
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Electrochemistry Communications, 2008
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