An amorphous metallic alloy Fe₇₈B₁₃Si₉ has a Curie temperature of 440℃ (713K) and a crystallization temperature of about 505℃ (778K). When the samples are annealed at well below the crystallization temperature, a stable α-Fe phase appears gradually with a further increase of an annealing time. Electron diffraction and X-ray study can identify the precipitated material in the amorphous matrix, however, it is quite difficult to give an accurate quantitative amount of this material. A new attempt to evaluate a quantitative atomic percentage of the precipitated material after successive heat treatments will be performed. As an example we report the result for a systematic study of an evaluation of the amount of α-Fe phase in the amorphous Fe-B-Si matrix at a 450℃ annealing. Using the changes of the mean magnetic moment, the quantitative determination of α-Fe can be made. The magnetization of Fe₇₈B₁₃Si₉ has been measured in the temperature range of 4.2 ＜ T ＜ 310 K at a constant magnetic field of 5.4 kOe using a homemade vibrating sample magnetometer. In order to get the value of magnetic moment at 0 K from the relevant extrapolation of the magnetization curve to T = 0 K, we present an exact analysis of spin-wave excitations in a presence of an applied magnetic field.
強磁性非晶質合金の結晶化過程におけるα-Feの析出量を磁気モーメントの変化量から求める試み : Fe₇₈B₁₃Si₉の場合
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