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Updated: Nov 28, 2025

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
Enhanced structural and magnetic properties of fcc colloidal crystals of cobalt nanoparticles
S Costanzo1, A T Ngo, V Russier
1Sorbonne Université, CNRS, De la Molécule aux Nano-Objets: Réactivité, Interactions Spectroscopies, MONARIS, 75005, Paris, France. isabelle.lisiecki@upmc.fr.
Abstract:
We report the elaboration of supercrystals made up of dodecanoic acid-coated 8.1 nm-Co nanocrystals with controlled supercrystallinity, morphology and magnetic properties. Supercrystal growth is controlled using a solvent-mediated ligand-ligand interaction strategy. Either face-centered cubic supercrystalline films or single colloidal crystals composed of cobalt nanocrystals are obtained. The change in supercrystal morphology is explained by Flory-type solvation theory using Hansen solubility colloidal parameters. The use of the same batch of Co nanocrystals for the fabrication of supercrystalline films and colloidal crystals enables accurate comparative structural and magnetic studies using (high-resolution) transmission electron microscopy, field emission gun scanning electron microscopy, grazing incidence small-angle X-ray scattering and vibrating sample magnetometry. The nearest neighbor distance between nanoparticles is interpreted using theoretical models proposed in the literature. We evidence the increase in both geometric anisotropy and magnetic dipolar interactions for colloidal crystals compared to supercrystalline films.
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