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High Coercive Field for Nanoparticles of CoFe 2 O 4 in Amorphous Silica Sol–Gel
Author(s) -
Hutlova A.,
Niznansky D.,
Rehspringer J.L.,
Estournès C.,
Kurmoo M.
Publication year - 2003
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.200305305
Subject(s) - coercivity , materials science , amorphous solid , nanoparticle , field (mathematics) , magnetization , dipole , sol gel , analytical chemistry (journal) , chemical engineering , condensed matter physics , nuclear magnetic resonance , magnetic field , nanotechnology , crystallography , organic chemistry , chemistry , physics , mathematics , quantum mechanics , pure mathematics , engineering
Unusually high magnetic hardness , characterized by a coercive field of 2 T at 2 K, has been observed for 12 nm particles of CoFe 2 O 4 (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.