Enhancing the magnetic anisotropy of maghemite nanoparticles via the surface coordination of molecular complexes : Nature Communications : Nature Publishing Group

Enhancing the magnetic anisotropy of maghemite nanoparticles via the surface coordination of molecular complexes.

Yoann Prado, Niéli Daffé, Aude Michel, Thomas Georgelin, Nader Yaacoub, Jean-Marc Grenèche, Fadi Choueikani, Edwige Otero, Philippe Ohresser, Marie-Anne Arrio, Christophe Cartier-dit-Moulin, Philippe Sainctavit, Benoit Fleury, Vincent Dupuis, Laurent Lisnard; Jérôme Fresnais

Nature Communications 6, 10139 (2015)

(a) Representation of the [Co(TPMA)Cl₂] complex used to enhance the magnetic anisotropy of the γ-Fe₂O₃ nanoparticles. (b) TEM image of the γ-Fe₂O₃ nanoparticles functionalized with the cobalt(II) complex: 1 (5.0 nm, σ=0.09) and (c) schematic view of the coordination of the complex with the iron ions. (d) Synthesis scheme with measured pH values, hydrodynamic diameters (Z_av), sizes (D) and distributions (σ).

Tuning the magnetic anisotropy in coordination nanoparticles: random distribution versus core–shell architecture.

Yoann Prado, Nada Dia, Laurent Lisnard, Guillaume Rogez, François Brisset, Laure Catala and   Talal Mallah

Chem. Commun. 48, 11455 (2012)

Core–shell magnetic coordination nanoparticles made of a soft core and a hard magnetic shell, containing anisotropic Co(II) ions, display a dramatic increase in their average blocking temperature with a coercive field value 25 times larger than that of the soft core, due to a large enhancement of the magnetic anisotropy.