Title :
Magnetic properties of Co/(CoNi)Fe2O4 nanocomposite magnet powders
Author :
Sugimoto, Satoshi ; Haga, Kazuaki ; Kagotani, Toshio ; Inomata, Koichiro
Author_Institution :
Dept. of Mater. Sci., Tohoku Univ., Sendai, Japan
Abstract :
Co/(CoNi)Fe2O4 nanocomposite powders were prepared by mixing coprecipitated (CoO)0.9(NiO)0.1·Fe2O3 nanoparticles with Co nanoparticles, which were synthesized by alcohol reduction. TEM observations reveal that the powder consists of Co and (CoO)0.9(NiO)0.1·Fe2O3 nanoparticles with an average particle size of 30-50 nm. While the coercivity (HcJ) is 156 kA/m, the saturation magnetization (σs) of 115.8 Am2/kg is obtained, which is comparable to that of Co nanoparticles. In the hysteresis loop, magnetization changes smoothly with field as the hysteresis behavior of a single-phase material. The high recoil ratio (Rrecoil) of 0.69 and the positive ΔM values suggest the presence of the exchange coupling between Co and (CoNi)Fe2O4 nanoparticles.
Keywords :
cobalt alloys; coercive force; exchange interactions (electron); iron alloys; magnetic particles; nanocomposites; nanoparticles; nickel alloys; transmission electron microscopy; 30 to 50 nm; Co-CoNiFe2O4; TEM; alcohol reduction; coercivity; exchange coupling; hysteresis loop; magnet powders; magnetic properties; nanocomposite powders; nanoparticles; saturation magnetization; single-phase material; Coercive force; Iron; Magnetic anisotropy; Magnetic properties; Nanoparticles; Perpendicular magnetic anisotropy; Powders; Saturation magnetization; Soft magnetic materials; Temperature; Alcohol reduction; coprecipitation; ferrite; nanocomposite; recoil;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2005.854955
