Study of the role of the ligands coordinated at the surface of pure Wüstite nanoparticles prepared following a room temperature organometallic method: Evidence of ferromagnetic – in shell- and antiferromagnetic – in core magnetic behaviors

Arnaud Glaria (1) , Myrtil L. Kahn (1) , Bruno Chaudret (2) , Pierre Lecante (3) , Marie-José Casanove (4) , Bernard Barbara (5)

1 LCC - Laboratoire de chimie de coordination
2 LPCNO - Laboratoire de physique et chimie des nano-objets
3 CEMES - Centre d'élaboration de matériaux et d'études structurales
4 CEMES-SINanO - Surfaces, Interfaces et Nano-Objets
5 NEEL - QuantECA - Circuits électroniques quantiques Alpes

Wüstite particles (Fe1−yO) are synthesized using controlled hydrolysis at room temperature of [Fe(N(SiMe3)2)2] and stabilized by amine ligands. This method leads to 5 nm pure wüstite particles. This phase is clearly identified by transmission electron microscopy and wide angle X-ray scattering. Distortion in the crystallographic structure has been demonstrated. Particular attention is paid on the Fe(III) formation. Moreover, a combination of Mössbauer spectroscopy and SQuID measurements, revealed that the particles are composed of an antiferromagnetic core surrounded by a ferromagnetic shell. According to the Néel theory, the Fe(III) and Fe(II) ions present in the particles are ferromagnetically coupled and the proportion of Fe(III) ions varies from 3.9 to 7.1% as a function of the amine ligand.

Mots clés: Wüstite; Nanoparticles; Organometallic chemistry; Magnetism

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Arnaud Glaria, Myrtil L. Kahn, Bruno Chaudret, Pierre Lecante, Marie-José Casanove, et al.. Study of the role of the ligands coordinated at the surface of pure Wüstite nanoparticles prepared following a room temperature organometallic method: Evidence of ferromagnetic – in shell- and antiferromagnetic – in core magnetic behaviors. Materials Chemistry and Physics, 2011, 129 (1-2), pp.605 - 610. ⟨10.1016/j.matchemphys.2011.04.077⟩. ⟨hal-01851631⟩