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Communication dans un congrès

New approach to closely-spaced disordered cobalt-graphene nanocomposites for non-conductive ferromagnetic films: from local structure to radio-electric properties

Abstract : The objective of this work is to synthesize closely-spaced disordered nanocomposites of cobalt for producing μm-thick films of non-conductive ferromagnet with high moment . Commercial graphene-coated nanoparticles (Co/C) are used since graphene prevents metallic core from oxidation (i .e . saturation magnetization of 150emu/g). Synthesis of nanocomposites is based on two original functionalization schemes. First Co/C are functionalized by non-covalently grafting low molecular weight pyrene-terminated polystyrene (Pyr-PS 1 ) on graphene to obtain Co/C//PyrPS 1 product . Second Co/C//PS 1 is produced by covalent in situ polymerization of styrene monomers . As a result, uniform outer-shell successfully forms (2-4nm thick) around the nanoparticles of Co/C and avoids electric percolation while promoting strong dipolar coupling at room temperature . Thereby, we report that core double-shell particles of Co/C//Pyr-PS 1 or Co/C//PS 1 assembled in closely-spaced arrangements are strong enough to sustain different magnetic orders (antiferromagnetic, ferromagnetic, “amorphous-like”) both in cast solutions and films . At the end, a second high molecular weight polystyrene PS 2 is used as an encapsulating matrix to form Co/C//Pyr-PS 1 /PS 2 or Co/C//PS 1 /PS 2 final product suitable for spin coating .
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Communication dans un congrès
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https://hal.univ-grenoble-alpes.fr/hal-01878059
Contributeur : Marielle Clot <>
Soumis le : jeudi 20 septembre 2018 - 15:53:27
Dernière modification le : vendredi 17 juillet 2020 - 09:10:08

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H. Takacs, V. Herman, B. Viala, J. Alarcon Ramos, J.-H. Tortai, et al.. New approach to closely-spaced disordered cobalt-graphene nanocomposites for non-conductive ferromagnetic films: from local structure to radio-electric properties. IEEE International Magnetics Conference (Intermag), May 2015, Pékin, China. ⟨10.1109/INTMAG.2015.7157080⟩. ⟨hal-01878059⟩

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