| 研究課題/領域番号 |
20K15027
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| 研究機関 | 京都大学 |
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研究代表者 |
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| 研究期間 (年度) |
2020-04-01 – 2025-03-31
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| キーワード | x-ray holography / site-selectivity / local atomic structure / local disorder |
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| 研究実績の概要 |
New advances in methods using x-ray fluorescence holography (XFH) have the potential to become a universal tool for site-selective investigations in crystals. These methods combine the intrinsic element-selectivity of XFH with the possibility for a chemical characterization of the environment. This is achieved by a resonant approach, i.e. tuning the x-ray energy to an energy that coincides with an x-ray absorption edge in the material.
The proposed project aims to practically implement such site-selective measurements and to apply them to current research issues in materials science. This approach is useful for, among else, identifying local atomic environments with chemical information and for understanding in detail the chemical disorder. One of the obstacles here is the atomic image cancellation effect, which leads to a large decrease in the signal intensity of certain pairs of distances and incident energies.
In this FY, the investigation using resonant XFH of a short-range-ordered Ni-Fe alloy was advanced. Furthermore, we investigated computationally the effect of various kinds of disorder on the holographic data to establish a reference for future experimental works. This approach was also employed to compare the data about local atomic disorder from holographic techniques with those from established methods like Diffuse Scattering. The XFH data are found to complement existing information well due to its site-selective properties.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
The project is progressing smoothly. Experiments at large-scale research facilities were conducted as planned, and another 2 experiments for FY 2024 are already approved.
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| 今後の研究の推進方策 |
In the further course of this research, it is planned to apply the insight gathered so far for a complex functional material, which is a High Entropy Alloy consisting of 6 principal elements. The site-selective investigations developed here can significantly push forward the current knowledge about the structure of these highly topical material system. In particular, it will be interesting to investigate whether short-range atomic order exists between specific elements, which can have a major impact on the material properties.
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| 次年度使用額が生じた理由 |
The remaining budget will be used for finishing the last experiments at large research facilities and the corresponding travel expenses, as well as for presentation of the scientific results of this project at international conferences.
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