Structural and magnetic properties of core–shell iron–iron oxide nanoparticles

• Published in: Journal of physics. Condensed matter Vol. 14; no. 49; pp. 13551 - 13567
• Main Authors: Kuhn, L Theil, Bojesen, A, Timmermann, L, Nielsen, M Meedom, Mørup, S
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 16.12.2002; Institute of Physics
• Subjects: Clusters, nanoparticles, and nanocrystalline materials; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Magnetic properties and materials; Magnetic properties of nanostructures; Nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals; Physics; Structure of solids and liquids; crystallography; Moessbauer effect; Inorganic compounds; Transition element compounds; Experimental study; Nanoparticles; Magnetite; Canted spin arrangements; High field; Magnetic structure; Oxidation; Sputter deposition; Iron oxides; Demagnetization; Nanocrystal; Crystal structure
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/14/49/311

We present studies of the structural and magnetic properties of core-shell iron-iron oxide nanoparticles. alpha -Fe nanoparticles were fabricated by sputtering and subsequently covered with a protective nanocrystalline oxide shell consisting of either maghaemite ( gamma -Fe sub 2 O sub 3 ) or partially oxidized magnetite (Fe sub 3 O sub 4 ). We observed that the nanoparticles were stable against further oxidation, and Mossbauer spectroscopy at high applied magnetic fields and low temperatures revealed a stable form of partly oxidized magnetite. The nanocrystalline structure of the oxide shell results in strong canting of the spin structure in the oxide shell, which thereby modifies the magnetic properties of the core-shell nanoparticles.