We have studied the magnetic properties of bcc-Fe fine particles With a diameter D of 3 ∼ 40 nm prepared by a vapor condensation process. The particles exhibit uniaxial anisotropy of 2.0 ∼ 3.0 × 106 erg/cc which is much larger than that of bulk Fe (0.5 × 106 erg/cc). Numerical calculations taking into account dipolar interaction and thermal agitation reproduce the particle size dependence of coercivity very well. According to the present work, magnetization reversal of Fe particles proceeds via coherent rotation for D < 15 ∼ 20 nm and via incoherent rotation for D > 15 ∼ 20 nm. It is, however, still uncertain why the magnetic anisotropy of Fe fine particles is uniaxial and so large.
- Dipolar interaction
- Fine particle
- Magnetic anisotropy
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering