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Séminaire Chimie ED459

Synthesis and self-assembly of iron oxide nanoparticles : looking at details from the atomic level to the mesoscale

Dr. German Salazar-Alvarez (Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, Sweden)

publié le

Le Jeudi 28 janvier 2016 à 13h45
UM FdS, Salle de Cours SC-16.01

Exchange-coupled magnetic nanoparticles are receiving a great deal of attention due to their potential applications.[1] Where, in recent years, a large number of methods to synthesize both single phase nanoparticles and hybrid nanoparticles comprised of two or more phases have been reported.[2,3] Moreover, the synthesis and self-assembly of non-spherical nanoparticles has been identified as one of the major challenges, and opportunities, for tomorrow’s materials.[4]

In this talk the correlation between microstructure and magnetic properties of biphasic core|shell Fe1–xO|Fe3–xO4 nanoparticles during their topotactic oxidation towards single-phase nanoparticles will be presented. We demonstrate that the anomalous magnetic properties of iron oxide core-shell nanoparticles are strongly correlated with defects in their interior which result in reduced saturation magnetization, high-field susceptibility, and exchange bias.[5,6] Varying the synthesis conditions it is possible to adjust their shape and size but also their quality so that they can be used to prepare large arrays.[7] Lastly, it will be shown the types of structures that can be obtained after self-assembling iron oxide truncated nanocubes into well-ordered three-dimensional arrays[8] where, combining detailed information from grazing incidence small-angle scattering (GISAXS) and transmission electron microscopy (TEM) measurements together with other additional techniques allow the reconstruction of the dominant phases, including defects at the mesoscale.[9]

References

1. J.H. Lee, et al, Nature Nanotechnology 2011, 6, 418.
2. L. Carbone, P.D. Cozzoli, Nano Today 2010, 5, 449.
3. G. Salazar-Alvarez, et al. J. Am. Chem. Soc. 2011, 133, 16738.
4. S.C. Glotzer, M.J. Salomon, Nature Materials 2007, 6, 557.
5. E. Wetterkog, et al, ACS Nano 2013, 7, 7132.
6. S. Disch et al. New J. Phys. 2012, 14, 013025.
7. E. Wetterskog, et al, Sci. Technol. Adv. Mater. 2014, 15, 055010.
8. S. Disch, et al, Nano Letters 2011, 11, 1651.
9. S. Disch, et al, Nanoscale 2013, 5, 3969.

Contact ICGM : Danielle Laurencin (équipe IMNO)

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