Magnetic anisotropy in Fe nanocrystals fabricated by GDM

Ferromagnetic nanocrystals composed of nano-sized grains show excellent soft magnetic characteristics and their mechanism is explained by a random anisotropy model(RAM). We have been studied nanocrystal systems with ferromagnetic 3d elements to understand the RAM. Fe nanocryatals were fabricated with a gas condensation and deposition method(GDM). The oxygen content in an as-deposited Fe nanocryatal was about 20 %. Hysteresis loop shifts observed in magnetic field cool measurements suggest the presence of antiferromagentic oxides. Dependence of room temperature coercive forces on the grain size(D) is not D⁶ but D^3.4. Magnetization curves often seen in thin films with stripe domain structures were observed at room temperature irrespective to the sort of substrates. The presence of perpendicular magnetic anisotropy was suggested.