High Coercive Field for Nanoparticles of CoFe2O4 in Amorphous Silica Sol–Gel

Authors

  • A. Hutlova,

    1. Groupe des Materiaux Inorganiques, Institut de Physique et Chimie des Materiaux de Strasbourg, UMR 7504, 23 rue du Loess, F-67034 Strasbourg Cedex, France
    2. Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic, CZ-250 68 Rez u Prahy, Czech Republic
    3. Department of Inorganic Chemistry, Faculty of Science, Charles University of Prague, Albertova 2030, CZ-128 40 Praha 2, Czech Republic
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  • D. Niznansky,

    1. Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic, CZ-250 68 Rez u Prahy, Czech Republic
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  • J.-L. Rehspringer,

    1. Groupe des Materiaux Inorganiques, Institut de Physique et Chimie des Materiaux de Strasbourg, UMR 7504, 23 rue du Loess, F-67034 Strasbourg Cedex, France
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  • C. Estournès,

    1. Groupe des Materiaux Inorganiques, Institut de Physique et Chimie des Materiaux de Strasbourg, UMR 7504, 23 rue du Loess, F-67034 Strasbourg Cedex, France
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  • M. Kurmoo

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  • This work was supported by the CNRS (France) and the Ministry of Education of the Czech Republic under the framework Project No. LN00 A028. AH and DN thank the French Research Ministry for supporting grants.

Abstract

Unusually high magnetic hardness, characterized by a coercive field of 2 T at 2 K, has been observed for 12 nm particles of CoFe2O4 (15%) in amorphous silica prepared by the sol–gel technique and sintered at 1000 °C. Field- and temperature-dependence magnetization data (see Figure) for these particles and those of 3.2 nm suggest that dipolar interaction between particles is responsible for this enhancement.

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