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
21 July, 2017

課題番号 Project No.

装置責任者 Name of responsible person

2017A0235

Toshiya Otomo

実験課題名 Title of experiment

装置名 Name of Instrument/（BL No.）

Mechanical milling dependences of short- and medium-range

BL-21 (NOVA)

structure in AgI-doped As2Se3 system

実施日 Date of Experiment

実験責任者名 Name of principal investigator

21 - 22 May, 2017 (27hr)

Takeshi Usuki
所属 Affiliation
Yamagata 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.
(AgI)x(As2Se3)1-x (x = 0.4, 0.6) with different milling periods (2, 10, 40h)

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.

Time of flight measurements were made at room temperature using a standard vanadium container for(AgI)x(As2Se3)1-x (x = 0.4, 0.6) samples (prepared by a mechanical milling method).

Figure 1 shows structure

factors S(Q) for 60 mol% AgI-doped samples with different milling periods (2, 10, 40h).

Although Bragg peaksof starting crystalline materials remain in the early stage of the milling, diffraction patterns at high Q regionchange little. On the other hand, it can be seen that there are large differences at low Q region especially at Q <3 Å-1.

A Bragg peak located at 1.75 Å-1 decreases with the milling, whereas a new peak seems to be appearedat around 1.25 Å-1, which is considered to be an indication of intermediate-range ordering (IRO) constructed byAs(Se1/2)3 pyramidal units.
Figure 2 gives pair distribution functions g(r) for the present samples with different milling periods.

A firstpeak located at 2.4 Å becomes larger with increasing milling time, indicating the formation of As-Se covalentbonds.

A hump at around 2.8 Å is related to the Ag-I bonds.

1It is of interest that curves of g(r) at the second

2. 実験方法及び結果（つづき） Experimental method and results (continued)
shell region between 4 and 5 Å largely change.
of AgI.

One of dominant contributions of these region is I-I correlation

The result therefore indicates that the deformation of I-I sub-lattice is seriously enhanced withincreasing milling time.

According to a previous report, the present system shows a large increase in their ionic

conductivity at the early stage of the milling [1].

Then, it can be predicted that disorderness around Ag ionswould be strongly related to the enhancement of the ionic conductivity in the present system. The threedimensional structure modelling using the reverse Monte Carlo method is now progressing for discussing deeply
the ionic diffusion mechanism in the present system.
[1] M. Sekine, Y. Suzuki, H. Ueno, Y. Onodera, T. Usuki, T. Nasu, S. Wei, J. Non-Crystalline Solids, 353 (2007)
2069-2073.

Figure 1 Total structure factors for AgI-doped glasses with different milling periods.

Figure 2 Total pair distribution functions for parent and AgI-doped glasses with different milling periods.

2