実験報告書様式（一般利用課題・成果公開利用）（ ※本報告書は英語で記述してください。ただし、産業利用課題として採択されている方は日本語で記述していただいても結構です。 ）MLF Experimental Report

提出日 Date of Report
4 July 2013

課題番号 Project No.

装置責任者 Name of responsible person

2012B0097

Toshiya Otomo

実験課題名 Title of experiment

装置名 Name of Instrument/（BL No.）

Structural analyses of Fe-based and Ni-based metal-metalloid amorphous alloys

BL21

実験責任者名 Name of principal investigator

実施日 Date of Experiment

Hiroshi Arima

March 21, 2013 (24 hours)

所属 Affiliation
Tohoku University
試料、実験方法、利用の結果得られた主なデータ、考察、結論等を、記述して下さい。（適宜、図表添付のこと）
Please report your samples, experimental method and results, discussion and conclusions. Please add figures andtables for better explanation.
1. 試料 Name of sample(s) and chemical formula, or compositions including physical form.

The following amorphous alloy samples were produced by the single-roller melt-spinning techniquewith boron metal enriched by 99 % 11B.
1.

Fe80B20 amorphous ribbon (thickness of 0.02 mm)

2.

Ni60B40 amorphous ribbon (thickness of 0.02 mm)

3.

Ni81B19 amorphous ribbon (thickness of 0.02 mm)

2. 実験方法及び結果 （実験がうまくいかなかった場合、その理由を記述してください。）
Experimental method and results.

If you failed to conduct experiment as planned, please describe reasons.

The neutron diffraction experiment was performed by using the time-of-flight technique and highintensity total diffractometer, NOVA at MLF, J-PARC. The amorphous ribbon samples were cut into 20mm length and loaded into a vanadium cylinder 6 mm in diameter. The typical duration of the datacollection time for each sample was about 4 hours. After the standard corrections for absorption,
multiple scattering and recoil factor, the measured intensity was converted into an absolute scale withrespect to the measured intensity of the vanadium standard. Pair distribution function g(r) was obtainedby the Fourier transformation of the structure factor S(Q).
Figure 1 shows S(Q) profiles of Fe80B20 calculated from the intensity profiles measured by a various
detector banks, as an example. Although S(Q) profiles at the high Q region is rather distorted probably
due to the insufficient correction for absorption, the oscillations around unity are observed up to about
25 Å-1. This result readily indicates that the present data processing works well and prompted us tostudy the detailed structure model by using the present experimental data. Figure 2 shows the g(r)s forFe80B20, Ni81B19, and Ni60B40 calculated by the interference functions up to Q max = 25 Å−1 .
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2. 実験方法及び結果（つづき） Experimental method and results (continued)

Fig. 1 The structure factor S(Q) for Fe80B20
amorphous alloy.

Fig. 2 The pair distribution functions for Fe80B20,
Ni81B19, Ni60B40.

The dashed lines in Fig.2 indicates the interatomic distances estimated from Goldschmidt atomic radii(Fe: 1.28 Å, Ni: 1.25 Å, B: 0.97 Å). At the nearest neighbor region up to about 3 Å, the first peak could
be accounted for a harmony of metal(M)–B and B–B pair correlations and the second peak is mainly
contributed by the M-M pair correlation.

Fig. 3 The interference functions from the neutron diffraction, ordinary X-ray diffraction, and AXS measurements
near Fe K absorption edge. Solid lines correspond to the experimental data. Dotted lines denote values
calculated by the RMC method.

As for the three dimensional structural modeling of the amorphous samples, reverse Monte Carlosimulation (RMC) has been performed starting from an initial model of 2,000 atoms with the b.c.c.
structure. The present simulation results are found to reproduce the three independent interferencefunctions obtained by the neutron diffraction, ordinary X-ray diffraction, and anomalous X-ray scattering(AXS) measurements as shown in Fig. 3. We are now analyzing the obtained structural model in detail,in order to clarify local structural units around B including their arrangement.

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