Variation of magnetic anisotropy by heat treatment of amorphous alloy (Co0.5Fe0.5)74.5Si13.5B12: amorphous phase and precipitated crystalline phases

Variation of the magnetic anisotropy by heat treatment of the ribbon formed ferromagnetic amorphous alloy (Co0.5Fe0.5)74.5Si13.5B12 was studied by Moessbauer and X-ray diffraction measurements. After very short time heat treatments near the crystallization temperature Tx, an amorphous state is still kept, but as the heat treatment periods and temperatures increase, the crystalline phases gradually precipitate. The average direction of the easy axis of magnetization of the amorphous phase remaining after the heat treatments becomes to make larger angle with the ribbon plane as compared with that of the as-prepared sample and the directional distribution of its component projected on the ribbon plane becomes isotropic. The crystalline phases precipitated at the early stage of crystallization have a similar directional distribution of the easy axis of magnetization as that in the amorphous matrix. In fully crystallized state, the directions of the magnetization axis of ferromagnetic domains point to all directions with equal weight. (orig.)