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
11 May, 2013

課題番号 Project No.

装置責任者 Name of responsible person

2012B0199

Toshiya Otomo

実験課題名 Title of experiment

装置名 Name of Instrument/（BL No.）

Neutron diffraction studies of AgI-doped As-chalcogenide glasses

BL-21 (NOVA)

実験責任者名 Name of principal investigator

実施日 Date of Experiment

Takeshi Usuki

11 -12 March, 2013 (24hr)

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(As2Te3)1-x (x = 0, 0.2, 0.4, 0.65)
glassy samples

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 time of flight measurements were made at room temperature using a standard vanadium container for(AgI)x(As2Te3)1-x (x = 0, 0.2, 0.4, 0.65). Figure 1 shows structure factors S(Q), where Q is scattering vector
magnitude, obtained by the neutron diffraction experiments for both parent As2Te3 and 65 mol% AgI-dopedglasses.

Diffraction patterns at high Q region for AgI doped and undoped glasses change little, since thesedepend mostly on the short-range covalent bonding of host As2Se3 glass.

On the other hand, it can be seen that

there are large differences at low Q region in the S(Q), especially at Q < 12 Å-1. A pre-peak at 1.25 Å-1 in parent
As2Te3 glass, which is considered to be an indication of intermediate-range ordering (IRO) constructed by theAs(Te1/2)3 helical chains, becomes weaker with the incorporation of AgI but remains clearly in the highly
AgI-doped glasses.
Figure 2 gives pair distribution functions g(r) for the present glasses.
2.62 Å in the host As2Te3 glass.

A well-defined first peak is found atWith addition of AgI, the first and second peaks shift toward higher r side.
12. 実験方法及び結果（つづき） Experimental method and results (continued)These changes correspond to the formation of the local atomic ordering constructed by Ag and I atoms.

Inorder to clarify such structure changes, we try to obtain quasi-partial pair distribution function of AgI-doped
glass, Δg(r), in which the As-Te pair correlation can be eliminated by the perfect cancellation of such correlation,using parent As2Te3 data.

Figure 2 includes Δg(r) for 65 mol% AgI-doped glasses.

Indeed, positions of firstand second peaks in Δg(r) agree well with nearest neighbour Ag-I and I-I distances in crystalline AgI, suggestingthat the environmental structure around mobile Ag ions in the present glasses seems to be similar to that incrystalline AgI. The present analysis for the short-range structure around As and mobile Ag atoms allows us topredict that the structure model for AgI-As2Te3 glasses is proposed to be a pseudo-binary mixture of theAs(Te1/2)3 network matrix and AgI-related conduction pathways.

It would be responsible for the high mobility

and diffusivity of mobile Ag ions in the highly doped glass systems.

Figure 1 Total structure factor for parent and AgI-doped glasses.

Figure 1 Total pair distribution function for parent and AgI-doped glasses.

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