Chapter 8
Magnetic Self-Assembling of Spherical
Co Nanoparticles Used as Building
Blocks: Syntheses, Properties and Theory
Johannes Richardi, C. Petit, and Isabelle Lisiecki
Abstract In this chapter, we show that thanks to the use of micellar and
organometallic approaches, one can favor the growth of uniform spherical Co NPs
with controlled surface passivation (dodecanoic acid or oleylamine), tunable size
(from around 4 to 9 nm) and tunable nanocrystallinity (from fcc to hcp structure). As a result of the balance between van der Waals attractions between the
metallic NPs, magnetic interactions between the magnetic NPs and solvent-mediated
interactions between ligands, these uniform colloidal NPs can be used as building
units to form a full set of assemblies which morphology depends on the deposition
strategy, involving solvent evaporation. In the case of spontaneous self-assembling
of magnetic NPs, compact hexagonal 2D arrays and 3D superlattices called supercrystals can form. In the latter case, either face-centered cubic supercrystalline films
or single colloidal crystals can be obtained. Mesostructures of hexagonally ordered
columns, labyrinths and void structures can result from assisted self-assembling,
induced by the application of an external magnetic field. In highly ordered superlattices, individual NPs act as “artificial atoms” and occupy the lattice sites to form
repetitive, periodic “artificial planes". From a fundamental point of view, these artificial solids constitute good models for investigating crystallization behavior. Resulting
from collective interactions between neighboring NPs, they exhibit novel magnetic
properties. The magnitude of these interactions, and then, the magnetic properties,
can be tuned by various parameters including (1) the (crystallographic) nature of
the magnetic NP, (2) the NP size, (3) the nature of the coating agent, (4) the nature
J. Richardi (B)
Sorbonne Université, CNRS, Laboratoire de Chimie Théorique, LCT, F. 75005 Paris, France
e-mail: johannes.richardi@sorbonne-universite.fr
URL: https://www.lct.jussieu.fr/pagesperso/richardi/jrichardi.html
C. Petit · I. Lisiecki (B)
Sorbonne Universités, UPMC Univ Paris 06, UMR 8233, MONARIS, 75005 Paris, France
e-mail: isabelle.lisiecki@upmc.fr
C. Petit
e-mail: christophe.petit@upmc.fr
J. Richardi · C. Petit · I. Lisiecki
CNRS, UMR 8233, MONARIS, 75005 Paris, France
© Springer Nature Switzerland AG 2021
D. Peddis et al. (eds.), New Trends in Nanoparticle Magnetism,
Springer Series in Materials Science 308,
https://doi.org/10.1007/978-3-030-60473-8_8
181
Magnetic Self-Assembling of Spherical
Co Nanoparticles Used as Building
Blocks: Syntheses, Properties and Theory
Johannes Richardi, C. Petit, and Isabelle Lisiecki
Abstract In this chapter, we show that thanks to the use of micellar and
organometallic approaches, one can favor the growth of uniform spherical Co NPs
with controlled surface passivation (dodecanoic acid or oleylamine), tunable size
(from around 4 to 9 nm) and tunable nanocrystallinity (from fcc to hcp structure). As a result of the balance between van der Waals attractions between the
metallic NPs, magnetic interactions between the magnetic NPs and solvent-mediated
interactions between ligands, these uniform colloidal NPs can be used as building
units to form a full set of assemblies which morphology depends on the deposition
strategy, involving solvent evaporation. In the case of spontaneous self-assembling
of magnetic NPs, compact hexagonal 2D arrays and 3D superlattices called supercrystals can form. In the latter case, either face-centered cubic supercrystalline films
or single colloidal crystals can be obtained. Mesostructures of hexagonally ordered
columns, labyrinths and void structures can result from assisted self-assembling,
induced by the application of an external magnetic field. In highly ordered superlattices, individual NPs act as “artificial atoms” and occupy the lattice sites to form
repetitive, periodic “artificial planes". From a fundamental point of view, these artificial solids constitute good models for investigating crystallization behavior. Resulting
from collective interactions between neighboring NPs, they exhibit novel magnetic
properties. The magnitude of these interactions, and then, the magnetic properties,
can be tuned by various parameters including (1) the (crystallographic) nature of
the magnetic NP, (2) the NP size, (3) the nature of the coating agent, (4) the nature
J. Richardi (B)
Sorbonne Université, CNRS, Laboratoire de Chimie Théorique, LCT, F. 75005 Paris, France
e-mail: johannes.richardi@sorbonne-universite.fr
URL: https://www.lct.jussieu.fr/pagesperso/richardi/jrichardi.html
C. Petit · I. Lisiecki (B)
Sorbonne Universités, UPMC Univ Paris 06, UMR 8233, MONARIS, 75005 Paris, France
e-mail: isabelle.lisiecki@upmc.fr
C. Petit
e-mail: christophe.petit@upmc.fr
J. Richardi · C. Petit · I. Lisiecki
CNRS, UMR 8233, MONARIS, 75005 Paris, France
© Springer Nature Switzerland AG 2021
D. Peddis et al. (eds.), New Trends in Nanoparticle Magnetism,
Springer Series in Materials Science 308,
https://doi.org/10.1007/978-3-030-60473-8_8
181