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An Organometallic Approach for Very Small Maghemite Nanoparticles: Synthesis, Characterization, and Magnetic Properties
Author(s) -
Glaria Arnaud,
Kahn Myrtil L.,
Falqui Andrea,
Lecante Pierre,
Collière Vincent,
Respaud Marc,
Chaudret Bruno
Publication year - 2008
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200800382
Subject(s) - maghemite , alkyl , nanoparticle , chemistry , transmission electron microscopy , chemical engineering , magnetic nanoparticles , crystallinity , group 2 organometallic chemistry , high resolution transmission electron microscopy , materials science , crystallography , organic chemistry , nanotechnology , molecule , engineering
Maghemite (γ‐Fe 2 O 3 ) nanoparticles stabilized by long‐alkyl‐chain amines are synthesized by using an organometallic approach. This method consists of the hydrolysis and oxidation of an organometallic precursor, Fe[N(SiMe 3 ) 2 ] 2 , in the presence of amine ligands as stabilizing agent in an organic solvent, namely tetrahydrofuran or toluene. Whatever the experimental conditions, particles with a diameter of 2.8 nm are obtained. The use of high‐resolution transmission electron microscopy and wide‐angle X‐ray scattering, together with Mössbauer spectroscopy and SQuId magnetometry, allows a complete characterization of these particles. Herein, we show that their structure is composed of a well‐ordered core surrounded by a more disordered shell. The size of the latter varies from 0.65 to 0.50 nm depending on the experimental conditions and is of prime importance for the understanding of the magnetic properties. We demonstrate that the shorter the alkyl chain length of the amine 1) the better the crystallinity of the particle’s core and 2) the stronger the interparticle interactions.