Development of electron differential interferometry and its application to magnetic materials

电子微分干涉技术的发展及其在磁性材料中的应用

• 批准号: 09555021
• 负责人: TANJI Takayoshi
• 金额: $ 7.17万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09555021/
• 关键词: electron holography; differential interferometry; differential microscopy; electron trapezoidal prism; real time phase observation; 電子系台形プリズム

Electron holography, which enables us to measure the electron phase shift with high precise and high resolution, requires a well-defined reference wave. This restricts the application to materials science. The theme of this research is to develop a new electron differential microscopy to overcome this disadvantage of electron holography and a system which makes a real time observation possible.Following results have been obtained in this project :i) In order to compensate for the lack of sensitivity in differential interferometry for weak phase objects, we proposed electron phase differential micrography that is realized by means of digital reconstruction method. For convenience an electron trapezoidal prism has been invented and replaced electron biprism.ii) We successfully observed directly the magnetic vectors in ferromagnetic thin films and that leaking from single magnetic domain particles by the two dimensional differentiation. It has been found that the reference phase reconstructed from all holograms should be coincident to each other, and an effect of Fresnel diffraction at an electron prism is important, too.iii) A complete simulation of electron holograms which include Fresnel effects, the quantum noise and the coherency of electrons has been accomplished.iv) Applying an additional square-wave voltage to the electron trapezoidal prism and recording double-exposure holograms on videotape, we confirmed that the real time observation in electron differential interferometry is available, though the time resolution obtained is about 1 sec. so far.

电子全息图使我们能够以高精确和高分辨率测量电子相移，需要明确定义的参考波。这限制了材料科学的应用。这项研究的主题是开发一种新的电子差异显微镜，以克服电子全息图和一种使实时观察的系统的缺点。在该项目中获得了实时观察的结果：i）为了补偿缺乏对弱相位对象的差异间隔对象的差异介入的敏感性，我们提出了Electon digital requortion Recons Insint requortim requornition。为了方便起见，已经发明了电子梯形棱镜并取代了电子二倍主义。已经发现，从所有全息图中重建的参考阶段应相互重建，并且在电子启发时在电子prism处的菲涅耳衍射的效果也很重要。录像带上的双曝光全息图，我们证实了电子差异干涉仪中的实时观察，尽管获得的时间分辨率约为1秒。迄今为止。

项目成果

K. Yamamoto: "Hologram simulation for off-axis electron holography"Ultramicroscopy. in press.

K. Yamamoto：“离轴电子全息术的全息图模拟”超显微镜。

T.Hanai: "Maximum entropy restoration of electron microscope images with random spatial distribution constraint" Scanning Microscopy. supl.11(発表予定). (1998)

T.Hanai：“具有随机空间分布约束的电子显微镜图像的最大熵恢复”扫描显微镜。11（待提交）。

花井孝明: "Maximum entropy restoration of electron microscope images with random spatial distribution constrait" Scanning Microscopy. supl. 11(発表予定). (1998)

Takaaki Hanai：“具有随机分布约束的电子显微镜图像的最大熵空间恢复”扫描显微镜 11（待提交）。

T. Hanai: "Reduction of spherical aberration of a transmission electron microscope by means of a foil lens"Electron Microscopy. 1. 82-84 (1998)

T. Hanai：“通过箔透镜减少透射电子显微镜的球差”电子显微镜。

平山司: "電子波干渉による電場・磁場の直視と材料科学への応用"まてりあ. 37・6. 454-460 (1998)

平山司：“通过电子波干涉直接观察电场和磁场及其在材料科学中的应用”Materia 37・6（1998）。