Spacing-dependent dipolar interactions in dendronized magnetic iron oxide nanoparticle 2D arrays and powders.
Fiche publication
Date publication
février 2013
Auteurs
Membres identifiés du Cancéropôle Est :
Dr GALLANI Jean-Louis
Tous les auteurs :
Fleutot S, Nealon GL, Pauly M, Pichon BP, Leuvrey C, Drillon M, Gallani JL, Guillon D, Donnio B, Begin-Colin S
Lien Pubmed
Résumé
Self-assembly of nanoparticles (NPs) into tailored structures is a promising strategy for the production and design of materials with new functions. In this work, 2D arrays of iron oxide NPs with interparticle distances tuned by grafting fatty acids and dendritic molecules at the NPs surface have been obtained over large areas with high density using the Langmuir-Blodgett technique. The anchoring agent of molecules and the Janus structure of NPs are shown to be key parameters driving the deposition. Finally the influence of interparticle distance on the collective magnetic properties in powders and in monolayers is clearly demonstrated by DC and AC SQUID measurements. The blocking temperature T(B) increases as the interparticle distance decreases, which is consistent with the fact that dipolar interactions are responsible for this increase. Dipolar interactions are found to be stronger for particles assembled in thin films compared to powdered samples and may be described by using the Vogel Fulcher model.
Référence
Nanoscale. 2013 Feb 21;5(4):1507-16