Study of the amorphous Fe100−x B x and (Fe70Co30)100−x B x powder prepared by borohydride reduction

The amorphous fine particles of Fe_100−x B _x (20.7≤x≤36.5) and (Fe₇₀Co₃₀)_100−x B _x (26.9≤x≤40.2) were prepared by borohydride reduction. The amorphous state of the samples was identified with both X-ray and electron diffraction measurements. With increasing boron content, the average hyperfine magnetic fields decrease. Comparing the hyperfine parameters of the glassy powder with those of the ribbons having the same compositions, the average hyperfine fields and the isomer shifts are different. The differences may be due to the amorphous polymorphism which is produced by the different preparation methods. Project is partly supported by the National Natural Science Foundation of China.