Development of depth-resolved soft X-ray absorption spectroscopy with fluorescence energy selection and observation of ionic conductor/ferro magnetic thin film interface

• Project/Area Number: 17K14324
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Condensed matter physics I
• Research Institution: Gunma University (2018); High Energy Accelerator Research Organization (2017)
• Principal Investigator: Suzuki-Sakamaki Masako 群馬大学, 大学院理工学府, 准教授 (90598880)
• Research Collaborator: AMEMIYA Kenta
• Project Period (FY): 2017-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000); Fiscal Year 2018: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2017: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
• Keywords: X線吸収分光 / 深さ分解 / 磁性薄膜 / イオン伝導体 / 表面・界面 / 電界効果 / 界面 / X線磁気円二色性 / 表面・界面物性 / Ｘ線

Outline of Final Research Achievements

To observe the chemical/magnetic state of the ferromagnetic thin film interface under the electric field, we develop the fluorescence yield depth-resolved soft x-ray absorption spectroscopy that is based on the electron yield depth-resolved technique. Interface analysis with a nm-depth resolution has been realizes. In this study, we develop the high signal-to-background (S/B) ratio depth-resolved soft XAS by fluorescence energy selection. We finally succeed obtaining the Fe and Co fluorescence selective XAS spectra of the FeCo thin film, and realize 100-times enhancement of the S/B ratio.

Academic Significance and Societal Importance of the Research Achievements

多くの積層デバイスにおいて、演算や記憶などの機能を担っているのは界面であり、さらなる機能の向上を目指すには界面の精密な電子状態を調べる必要がある。界面を直接観察する手法は限られ、特に分光学的な分析法は我々が開発を行う深さ分解XAS法が唯一の手法である。さらに最近ではよりデバイスの動作状態に近い環境で界面観察をする手法が求められており、本研究で開発した蛍光分光型深さ分解XAS法を用いることで、電場や磁場がある環境でも高感度に界面の化学・磁気状態を観察することが可能となった。nmの深さ分解能で界面状態を直接観察するオペランド分析法として、多くの積層デバイスへの応用が期待できる。

Research Products

• [Journal Article] Observation of an electric field-induced interface redox reaction and magnetic modification in GdOx/Co thin film by means of depth-resolved X-ray absorption spectroscopy (2018)
  • Author(s): Sakamaki Masako、Amemiya Kenta
  • Journal Title: Physical Chemistry Chemical Physics Volume: 20 Issue: 30 Pages: 20004-20009
  • DOI: 10.1039/c8cp02972e
  • Peer Reviewed
• [Journal Article] Development of high signal-to-background ratio depth-resolved soft X-ray absorption spectroscopy by fluorescence energy selection (2018)
  • Author(s): Suzuki-Sakamaki Masako、Amemiya Kenta
  • Journal Title: Japanese Journal of Applied Physics Volume: 57 Issue: 12 Pages: 120308-120308
  • DOI: 10.7567/jjap.57.120308
  • NAID: 210000149835
  • Peer Reviewed
• [Journal Article] Effect of interface NiO layer on magnetism in Fe/BaTiO3 thin film (2018)
  • Author(s): Masako Sakamaki and Kenta Amemiya
  • Journal Title: Japanese Journal of Applied Physics Volume: 印刷中
  • NAID: 210000149600
  • Peer Reviewed
• [Journal Article] Nanometer-resolution depth-resolved measurement of florescence-yield soft x-ray absorption spectroscopy for FeCo thin film (2017)
  • Author(s): Sakamaki M.、Amemiya K.
  • Journal Title: Review of Scientific Instruments Volume: 88 Issue: 8
  • DOI: 10.1063/1.4986146
  • Peer Reviewed
• [Presentation] 蛍光収量深さ分解XAFS法による外場中界面分析 (2018)
  • Author(s): 酒巻真粧子、雨宮健太
  • Organizer: 2017年度量子ビームサイエンスフェスタ、茨城県立県民文化センター（茨城・水戸）
• [Presentation] 蛍光収量型深さ分解XAFS法による磁場中界面分析 (2018)
  • Author(s): 酒巻真粧子、雨宮健太
  • Organizer: 第73回日本物理学会年次大会、東京理科大学野田キャンパス（千葉・野田）
• [Presentation] Direct observation of electric-field effect on interface magnetic state of GdOx/Co thin films by fluorescence-yield depth-resolved soft x-ray absorption spectroscopy (2018)
  • Author(s): M. Sakamaki and K. Amemiya
  • Organizer: The 17th International Conference on X-ray Absorption Fine Structure (XAFS 2018) (Krakow, Poland) (Poster)
  • Int'l Joint Research
• [Presentation] 精密界面分析に向けた蛍光分光深さ分解XAFS法の開発 (2018)
  • Author(s): 酒巻真粧子、雨宮健太
  • Organizer: 第21回XAFS討論会、北海道大学（北海道・札幌）
• [Presentation] 蛍光収量深さ分解XAFS法による外場中界面分析 (2018)
  • Author(s): 酒巻真粧子，雨宮健太
  • Organizer: 2017年度量子ビームサイエンスフェスタ、茨城県立県民文化センター（茨城・水戸）
• [Presentation] NiO/Ni/Cu(001) における磁気異方性の制御 (2018)
  • Author(s): 雨宮健太，酒巻真粧子
  • Organizer: 第73回日本物理学会年次大会、東京理科大学野田キャンパス（千葉・野田）
• [Presentation] 蛍光収量型深さ分解XAFS法による磁場中界面分析 (2018)
  • Author(s): 酒巻真粧子，雨宮健太
  • Organizer: 第73回日本物理学会年次大会、東京理科大学野田キャンパス（千葉・野田）
• [Presentation] Depth profile of surface oxidation on FeCo thin film by depth resolved X-ray absorption spectroscopy (2017)
  • Author(s): M. Sakamaki and K. Amemiya
  • Organizer: The 21st Interdisciplinary Surface Science Conference (ISSC-21), Manchester (UK)
  • Int'l Joint Research
• [Presentation] Effect of Electric Field on Magnetism of Ni Thin Films via Antiferromagnetic NiO (2017)
  • Author(s): K. Amemiya and M. Sakamaki
  • Organizer: The 8th International Symposium on Surface Science (ISSS-8), Tsukuba International Congress Centre (Ibaraki・Tsukuba)
  • Int'l Joint Research
• [Presentation] Observation of the electric-field effect in Fe/BaTiO3 thin films with the interface oxide layers (2017)
  • Author(s): M. Sakamaki and K. Amemiya
  • Organizer: The 8th International Symposium on Surface Science (ISSS-8), Tsukuba International Congress Centre (Ibaraki・Tsukuba)
  • Int'l Joint Research
• [Presentation] 蛍光収量型深さ分解XMCD法による磁性薄膜研究 (2017)
  • Author(s): 酒巻真粧子，雨宮健太
  • Organizer: 東北大学金属材料研究所共同利用ワークショップ、東北大学金属材料研究所（宮城・仙台）
• [Remarks] 電場・磁場中で薄膜の深さ方向ナノメーター分解能を実現
  • URL: https://www.kek.jp/ja/NewsRoom/Release/pressrelease20170808.pdf