Air- and water-resistant noble metal coated ferromagnetic cobalt nanorods

Sergio Lentijo (1) , Reasmey Phary Tan (1) , Cécile Marcelot (1, 2) , Thomas Altantzis (3) , Pier-Francesco Fazzini (1) , Teresa Hungría (1) , Benoit Cormary (1) , James R. Gallagher (4) , Jeffrey T Miller (4) , Hervé Martinez (5) , S. Schrittwieser (6) , J. Schotter (6) , Marc Respaud (1) , S. Bals (3) , G.V. Tendeloo (3) , Christophe Gatel (2) , K. Soulantika (1)

1 LPCNO - Laboratoire de physique et chimie des nano-objets
2 CEMES - Centre d'élaboration de matériaux et d'études structurales
3 Electron Microscopy for Materials Science - EMAT (Antwerp, Belgium)
4 Chemical Sciences and Engineering Division [Argonne]
5 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux
6 AIT - Austrian Institute of Technology [Vienna]

Cobalt nanorods possess ideal magnetic properties for applications requiring magnetically hard nanoparticles. However, their exploitation is undermined by their sensitivity toward oxygen and water, which deteriorates their magnetic properties. The development of a continuous metal shell inert to oxidation could render them stable, opening perspectives not only for already identified applications but also for uses in which contact with air and/or aqueous media is inevitable. However, the direct growth of a conformal noble metal shell on magnetic metals is a challenge. Here, we show that prior treatment of Co nanorods with a tin coordination compound is the crucial step that enables the subsequent growth of a continuous noble metal shell on their surface, rendering them air- and water-resistant, while conserving the monocrystallity, metallicity and the magnetic properties of the Co core. Thus, the as-synthesized core-shell ferromagnetic nanorods combine high magnetization and strong uniaxial magnetic anisotropy, even after exposure to air and water, and hold promise for successful implementation in in vitro biodiagnostics requiring probes of high magnetization and anisotropic shape. © 2015 American Chemical Society.

Mots clés: cobalt; Cobalt compounds; core-shell; Core shell; Metals; Anisotropic shapes; Anisotropy; High magnetization; Ferromagnetism; Ferromagnetic materials; ferromagnetic; Chemicals removal (water treatment); Metal coatings; Nanomagnetics; Uniaxial magnetic anisotropy; Tin coordination; Shells (structures); Precious metals; nanorods; Magnetic anisotropy; Magnetic metals; Magnetic properties; Magnetism; Magnetization; water resistant

Domaines: Chimie; Matériaux

Sergio Lentijo, Reasmey Phary Tan, Cécile Marcelot, Thomas Altantzis, Pier-Francesco Fazzini, et al.. Air- and water-resistant noble metal coated ferromagnetic cobalt nanorods. ACS Nano, 2015, 9 (3), pp.2792--2804. ⟨10.1021/nn506709k⟩. ⟨hal-01503972⟩