Development of electron holography in consideration of a dynamical electron diffraction for electromagnetic field analysis
| Project/Area Number |
15K06419
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Physical properties of metals/Metal-base materials
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| Research Institution | Tohoku University |
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Principal Investigator |
Akase Zentaro 東北大学, 多元物質科学研究所, 講師 (90372317)
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| Research Collaborator |
Shindo Daisuke
Murakami Yasukazu
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| Project Period (FY) |
2015-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000)
Fiscal Year 2017: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2016: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2015: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
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| Keywords | 透過電子顕微鏡 / 電子線ホログラフィー / 位相シフト / 動力学的電子回折 / 動力学的回折効果 |
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| Outline of Final Research Achievements |
With recent improvements in the precision and sensitivity of electron holography, the effect of dynamical electron diffraction on the phase shift has become important. In this study, we investigated the effect of dynamical electron diffraction on the phase shift in electron holography. Holograms were recorded from a wedge-shaped specimen of single-crystal Si around a Bragg diffraction condition. The results shows that an effective inner potential depends on the direction of the incident electron beam, especially near the Bragg condition. The characteristic phase shift was analyzed using dynamical electron diffraction theory (Bethe method). When excitation error sg < 0, the gradient of the phase-shift is high. On the other hand, when sg > 0, the gradient of the phase-shift is low. Under an exact Bragg diffraction condition, the phase shift jumps by π where the dark thickness fringes appear in the corresponding bright-field image.
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| Academic Significance and Societal Importance of the Research Achievements |
電子線ホログラフィーや微分位相コントラストSTEM法など透過電子顕微鏡を用いた電磁場解析手法をもちいて結晶性の試料を解析する際、しばしば電子線の回折現象が精確な解析の妨げとなり、ブラッグ条件からなるべく外した条件でホログラムを撮影する処置がとられてきた。しかし、実用材料への展開が進む中、結晶粒界における磁場解析等、回折による位相変化を考慮すべき課題が増えていた。そこで、本研究では電子線の試料中での多重散乱を考慮した動力学的回折理論をもちいて、結晶試料内部の電子線の振る舞いをより正確に把握することを目指した。本研究により、電磁場解析の回折現象が大きくかかわる研究課題へのアプローチ方法が示された。
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Report
(5 results)
Research Products
(9 results)
