Magnetic Anisotropy in an Amorphous Fe80P13C7 Alloy

The temperature dependence of the uniaxial magnetic anisotropy Ku was examined using a high sensitivity torque magnetometer. Ku exists even after the rough surface and striations in the ribbon of rapidly quenched amorphous alloy, Fe80P13C7, were removed. The values of Ku are 0.7 to 1.4×104 erg/cm3 at room temperature and they decrease until about the Curie point (340°C) is reached with a slight kink at about 210°C. The magnetic anisotropies of sucked alloys, Fe100-xPx (16.3≦x≦26.6) and Fe100-xCx (3.8≦x≦18.2), which are the constitutional alloys of the crystallized alloy, Fe80P13C7, were also studied. The uniaxial magnetic anisotropy in the amorphous Fe80P13C7 alloy cannot be explained either by uniaxial stress or directional pair ordering. The magnetic anisotropy can be explained by the fine crystallites of Fe3P and Fe3C alloys in the amorphous matrix of an Fe80P13C7 alloy.