ヒメダイヤの新たな応用－蛍光X線ホログラフィーの高圧下での測定に成功～特定元素周りの原子位置の3次元的可視化～

2025-07-22 愛媛大学

今回の実験成功の鍵となるヒメダイヤ製のダイヤモンドアンビル。このアンビルを2つ対向させ、平らにした先端の間に実験試料を挟み、10万気圧以上の高圧を発生させる。

＜関連情報＞

• https://www.ehime-u.ac.jp/data_relese/pr_20250718_grc/
• https://www.ehime-u.ac.jp/wp-content/uploads/2025/07/pr_20250718_grc.pdf
• https://journals.iucr.org/s/issues/2025/05/00/ok5136/index.html

高圧環境下での蛍光X線ホログラフィー
X-ray fluorescence holography under high-pressure conditions

Xinhui Zhan, Naoki Ishimatsu, Koji Kimura, Naohisa Happo, Halubai Sekhar, Tomoko Sato, Nobuo Nakajima, Naomi Kawamura, Kotaro Higashi, Oki Sekizawa, Hirokazu Kadobayashi,^gRitsuko Eguchi, Yoshihiro Kubozono, Hiroo Tajiri, Shinya Hosokawa, Tomohiro Matsushita, Toru Shinmei, Tetsuo Irifune and Koichi Hayashi
Journal of Synchrotron Radiation  Published:18 July 2025
DOI:https://doi.org/10.1107/S1600577525005284

This study reports the first application of X-ray fluorescence holography (XFH) under high-pressure conditions. We integrated XFH with a diamond anvil cell to investigate the local structure around Sr atoms in single-crystal SrTiO₃ under high pressure. By utilizing nano-polycrystalline diamond anvils and a yttrium filter, we effectively eliminated significant background noise from both the anvils and the gasket. This optimized experimental configuration enabled the measurement of Sr Kα holograms of the SrTiO₃ sample at pressures up to 13.3 GPa. The variation of lattice constants with pressure was calculated by the shifts of Kossel lines, and real-space images of the atomic structures were reconstructed from the Sr Kα holograms at different pressures. This work successfully demonstrates the feasibility of employing XFH under high-pressure conditions as a novel method for visualizing pressure-induced changes in the three-dimensional local structure around the specified element.