title: Enhanced magnetization in highly crystalline and atomically mixed bcc Fe-Co nanoalloys prepared by hydrogen reduction of oxide composites.
abstract: Fe(x)Co(100-x) nanoalloys (NAs) with 20 ≤ x ≤ 80 were prepared by hydrogen reduction of Fe-Co oxide nano-composites, which were composed of mixed phases (or domains) of Fe(2)O(3) and CoO. In situ X-ray diffraction (XRD) measurements using synchrotron radiation clearly showed development of a solid-solution Fe-Co phase by hydrogen reduction from the oxide composites. High-resolution transmission electron microscopy (TEM), high-angle annular dark-field scanning TEM and powder XRD revealed that Fe-Co NAs form a single crystal structure and the two elements are mixed homogeneously. The saturation magnetization depends on the size and metal composition and shows the highest value (250 emu g(-1)) for the Fe(70)Co(30) NA in the size range of 30-55 nm, which is comparable to that of the Fe(70)Co(30) bulk alloy (245 emu g(-1)). This high magnetization is attributable to high crystallinity and homogeneous mixing of constituent atoms, which are attained by thermal treatment of oxide phases under a hydrogen atmosphere.
authors: Catalysis Research Center, Hokkaido University, Nishi 10, Kita 21, Sapporo 001-0021, Japan.
authors: Md Jafar
authors: MJ
authors: Sharif
authors: Miho
authors: M
authors: Yamauchi
authors: Shoichi
authors: S
authors: Toh
authors: Syo
authors: S
authors: Matsumura
authors: Shin-ichiro
authors: S
authors: Noro
authors: Kenichi
authors: K
authors: Kato
authors: Masaki
authors: M
authors: Takata
authors: Tatsuya
authors: T
authors: Tsukuda
mesh_terms: D000497:Alloys / Q000737:chemistry; D003035:Cobalt / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D006859:Hydrogen / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D046911:Macromolecular Substances / Q000737:chemistry; D060526:Magnetic Fields; D059346:Magnets; D008422:Materials Testing; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D000497:Alloys; D046911:Macromolecular Substances; D010087:Oxides; D003035:Cobalt; D006859:Hydrogen; D007501:Iron