High-resolution Electron Microscopy of Labradorite Feldspar

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Using the aberration-free focus (AFF) imaging condition in tilted illumination and by adjusting the thickness of gold crystals to optimum values, the electron-microscope images of gold atoms in perfect crystals are formed at the correct positions of atoms with a resolution higher than the theoretical resolution limit in normal operation. This method is applied to observe the images of atoms in gold crystals containing planar defects such as twin boundaries and stacking faults. The observed contrast of the images is compared with theoretical calculations based on both the HowieWhelan theory of electron diffraction in many-beam form and an electron image-formation theory. The agreement between observations and theoretical cap culations is fairly good.

Section: Introductionmentioning

confidence: 99%

Electron-microscope images of the crystal lattice of gold containing planar defects

Takai¹,

Hashimoto²,

Endoh³

1983

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“…Even though the waves of low-order Bragg reflections are included in the imaging, many higherorder Bragg reflections that are excited at a high t~ 1985 International Union of Crystallography voltage are scattered outside the aperture and contribute to the contrast of the images of imperfections. This method has many attractive features for the study of crystal-lattice imperfections and it will be referred to as the multi-beam-imaging (MBI) method (Hashimoto, 1971;Hashimoto, Endoh, Kumao, Shiraishi & Nishigori, 1974). This method is equivalent to observing an atomic structure image but is limited by the contrast variation of the background.…”

Section: Introductionmentioning

confidence: 99%

Characterization of lattice imperfections by the multi-beam-imaging method in high-voltage electron microscopy

Endoh¹,

Hashimoto²,

Nishigori³

et al. 1985

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It is the purpose of this paper to introduce and discuss the multi-beam-imaging (MBI) method for studying lattice imperfections in high-voltage electron microscopy. The image contrast is compared with the theoretical contrast based on the many-beam dynamical theory of electron diffraction; the effect of absorption is included in the calculation. It is shown that the nature of imperfections can be studied from only one image taken by the MBI method instead of the brightand dark-field images that are generally used. Further, the images of a thick crystal taken by the MBI method become much brighter than the ordinary bright-field and dark-field images. Finally, the technique is applied to the characterization of stacking faults and screw dislocations in thick regions observed in the 1 MeV electron microscope.

“…Thon (1966) and Erickson & Klug (1971) have shown that the optical diffraction pattern of a high-resolution electron-microscope image of amorphous material shows the spatial frequency of the recorded image. Hashimoto, Tanji, Ono & Kumao (1975) have shown briefly that crystal lattices of labradorite feldspar can be studied from the optical diffraction pattern of its high-resolution electronmicroscope images. Clarke & Thomas (1976) and Gronsky, Sinclair & Thomas (1976) have applied this technique to the study of the structure of ceramics and metals.…”

Section: Introductionmentioning

confidence: 99%

Optical selected-area diffraction patterns of high-resolution electron-microscope images for crystal analysis

Tanji¹,

Hashimoto²

1978

Self Cite

Optical selected-area diffraction patterns made from high-resolution electron micrographs of crystals have been used as a source of diffraction information from areas as small as a single unit cell of the crystal. The intensities of the electron diffraction pattern of the specimen crystal and the optical diffraction patterns of high-resolution electron-microscope images have been discussed by electron optical image formation theory taking account of spherical aberration and defocusing of the objective electron lens and it is concluded that the optical diffraction pattern may be identical with the electron diffraction pattern if the electron micrograph is photographed under optimum conditions. Optical diffraction patterns from areas of 80, 30 and 10 A in diameter of labradorite feldspar have been taken and the orientation of two adjoining grains, 30 /k in diameter, has been determined. The diffraction pattern from a unit-cell area has also been taken and compared with the calculated intensity.