[S-CG50] 地球惑星科学におけるレオロジーと破壊・摩擦の物理

[SCG50-09] 地球惑星物質の局所変形評価に向けた電子回折イメージング

★招待講演

*伊神 洋平¹、三宅 亮¹ (1.京都大学理学研究科)

キーワード：電子顕微鏡法、電子回折、局所変形、結晶選択配向

It remains challenging in mineralogy to reveal micro/nanometric heterogeneity of crystal structure and the relevant properties within naturally occurring minerals. Electron microscopy is acknowledged to be effective to tackle the issue. Recently developed scanning transmission electron microscopy (STEM) provides extremely high spatial resolution to directly visualize atomic arrangement of crystalline materials, but the field of view is too limited to grasp their nanometer/micrometer-scale heterogeneity. Thus, we focus on an alternative method which uses an electron nanoprobe to record many two-dimensional (2D) diffraction patterns over a 2D grid of probe positions from nanometer/micrometer regions. This approach (diffraction imaging, 4D-STEM [1]) is able to evaluate crystal structural parameters at each probe position with a clear STEM image. In the presentation, we will introduce our mineralogical and Earth/planetary scientific applications of the technique.
If unexpected local-deformation process exists in some Earth/planetary material, it may crucially affect the bulk mechanical properties in various situations. The diffraction imaging technique would be effective also to solve the problem, because this technique enables us to evaluate lattice strain, crystal preferred orientation and dislocation property within the samples having complex mineralogical/petrological textures.

Reference
[1] Ophus, C. (2019) Microsc. Microanal. 25, 563.