UFAS1 PLATFORM EVENTS, International Conference on Materials Science ICMS2018

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Non-aqueous Sol-Gel Routes to Magnetic Nanoparticles
Mohamed Karmaoui

Last modified: 2018-07-25

Abstract


General interest in magnetic nanoparticles (MNPs) has grown due to the need generated by novel biomedical, diagnostic, and therapeutic applications. Nanosized magnetic materials play a major role in the development of functional nanoscaled devices. It is essential to understand the relationship between NPs synthesis and the resultant magnetic properties. Moreover, the tendency is to achieve the goal of a single domain within one NPs, which will allow the tailoring of resulting magnetic properties. Therefore, making ultrasmall NPs (below the single magnetic domain size limit), with a narrow size distribution (monodisperse), is crucial to increase the maximum information density in magnetic recording, to optimize the magnetic

coupling, and to increase the volume of soft magnetic phase in permanent magnet nanocomposites.

Non-aqueous sol-gel routes are remarkably successful for the synthesis of bimetallic and multi-metal oxide nanoparticles. Solvent assisted synthesis and especially the "benzyl alcohol route" have several advantages such as a low reaction temperature and a high crystallinity and purity of the as synthesized oxides.[1-3] Here, we present the synthesis, characterization and magnetic properties of bimetallic CoPt3 and multi metal oxide CoFe2O4 nanoparticles achieved by the "benzyl alcohol route". This non-aqueous sol-gel method is suitable in this case as it allow the synthesis of high quality nanocrystals where no others solvent were involved on the reactions.

The highly monodisperse powder CoPt3 and CoFe2O4 nanoparticles were investigated with innovative advanced X-ray methods (XRD), whole powder pattern modeling (WPPM), high-resolution scanning transmission electron microscopy (HR-STEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Raman, Msbauer spectroscopy and superconducting quantum interference device (SQUID) magnetometry. In these systems, the magnetic properties seem to be strongly dependent on the metal oxide precursor and thus, on the synthetic conditions. The magnetic properties were studied and were correlated to the oxidation state of the NPs.

Keywords: CoPt3, CoFe2O4, nanoparticles, magnetism properties

References:

1. Green, M., Organometallic based strategies for metal nanocrystal synthesis. Chemical Communications 2005, (24), 3002-3011.

2. Karmaoui, M.; Silva, N. J. O.; Amaral, V. S.; Ibarra, A.; Mill, ; Palacio, F., Synthesis of cobalt aluminate nanopigments by a non-aqueous sol-gel route. Nanoscale 2013, 5 (10), 4277-4283.

3. Karmaoui, M.; Amaral, J. S.; Lajaunie, L.; Puliyalil, H.; Tobaldi, D. M.; Pullar, R. C.; Labrincha, J. A.; Arenal, R.; Cvelbar, U., Smallest Bimetallic CoPt3 Superparamagnetic Nanoparticles. The Journal of Physical Chemistry Letters 2016, 7 (20), 4039-4046.