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EELS investigation of FeCo/SiO 2 nanocomposites
Author(s) -
Falqui A.,
Serin V.,
Calmels L.,
Snoeck E.,
Corrias A.,
Ennas G.
Publication year - 2003
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1046/j.1365-2818.2003.01177.x
Subject(s) - materials science , transmission electron microscopy , magnetic moment , nanocomposite , electron energy loss spectroscopy , nanoparticle , layer (electronics) , oxide , surface layer , spectroscopy , analytical chemistry (journal) , chemical engineering , nanotechnology , condensed matter physics , chemistry , metallurgy , physics , quantum mechanics , chromatography , engineering
Summary The factors that determine the local magnetic properties of FeCo/SiO 2 nanocomposite powders and films have been analysed by electron energy‐loss spectroscopy (EELS) and transmission electron microscopy (TEM). Attention has been given to the chemical composition, the local electronic structure and the atomic arrangement. The results show that the nanoparticles from sol‐gel prepared powders are generally Fe‐rich, whereas they are Co‐rich in sol‐gel prepared films. In addition, a subnanometre oxide layer at the surface of the FeCo nanoparticles has been clearly observed in the powder sample. It is found that the magnetic moment should be partly governed by alloying effects. Numerical values of the near‐surface magnetic moment have been obtained using the ab‐initio layer‐KKR method. These values should be helpful in understanding the layer‐by‐layer changes of the white line ratio close to the surface of the nanoparticles.