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Internal Structure and Magnetic Properties in Cobalt Ferrite Nanoparticles: Influence of the Synthesis Method
Author(s) -
Lavorato Gabriel,
Alzamora Mariella,
Contreras Cynthia,
Burlandy Gabriel,
Litterst F. Jochen,
BaggioSaitovitch Elisa
Publication year - 2019
Publication title -
particle and particle systems characterization
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.877
H-Index - 56
eISSN - 1521-4117
pISSN - 0934-0866
DOI - 10.1002/ppsc.201900061
Subject(s) - materials science , nanoparticle , magnetic moment , magnetic nanoparticles , magnetization , spin canting , cobalt , magnetic anisotropy , saturation (graph theory) , ferrite (magnet) , nuclear magnetic resonance , chemical physics , analytical chemistry (journal) , magnetic field , nanotechnology , condensed matter physics , chemistry , composite material , metallurgy , physics , mathematics , quantum mechanics , combinatorics , chromatography
The design of novel nanostructured magnetic materials requires a good understanding of the variation in the magnetic properties due to different synthesis conditions. In this work, four different procedures for fabricating Co‐ferrite nanoparticles with similar sizes between 7 and 10 nm are compared by studying their structural and magnetic properties. Non‐aqueous methods based on the thermal decomposition of metal acetylacetonates at high temperatures, either with or without surfactants, provide highly crystalline nanoparticles with large saturation magnetization values and a coherent reversal of the magnetic moment. However, variations in the density of defects and in the shape of the nanocrystals determine the distribution of switching fields and the effective magnetic anisotropy, which reaches up to ≈1 × 10 7 erg cm −3 for oleic acid‐capped 9 nm nanoparticles. It is shown that the saturation magnetization values for nanoparticles produced by different methods are in the range between 49 and 95 emu g −1 due to differences in the stoichiometry, in the cation occupancy, in the magnetic disorder and in the spin canting of the magnetic sub‐lattices, the latter evaluated by in‐field Mössbauer spectroscopy.