Application of the imaging plate to quantitative analysis of electron-diffraction and high-resolution electron microscopy

Author(s):  
K. Hiraga ◽  
D. Shindo ◽  
M. Hirabayashi ◽  
T. Oikawa ◽  
N. Mori ◽  
...  

The “Imaging Plate” (IP) has three superior characteristics, i.e., high sensitivity to the electron beam, and a wide dynamic range and good linearity for electron dose compared with conventional EM films. The use of the IP is expected to lead to quantitative analysis of electron microscopy. The purpose of the present work is to examine the possibility of application of the IP to the quantitative analysis of electron diffraction and high-resolution electron microscopy.By using the TEM-IP System developed by Oikawa et al., which is published in this conference, electron diffraction patterns and high-resolution electron micrographs taken on the IP with an effective size of 102 х 77 mm2 were convertedinto digital data of 2048 х 1536 pixels with 4096 gray levels. Observations of electron diffraction patterns and high-resolution electron micrographs were made with a 200 kV (JEM-2000FX) and a 400 kV (JEM-4000EX) electron microscope, respectively.

2001 ◽  
Vol 16 (1) ◽  
pp. 101-107 ◽  
Author(s):  
Takeo Oku ◽  
Jan-Olov Bovin ◽  
Iwami Higashi ◽  
Takaho Tanaka ◽  
Yoshio Ishizawa

Atomic positions for Y atoms were determined by using high-resolution electron microscopy and electron diffraction. A slow-scan charge-coupled device camera which had high linearity and electron sensitivity was used to record high-resolution images and electron diffraction patterns digitally. Crystallographic image processing was applied for image analysis, which provided more accurate, averaged Y atom positions. In addition, atomic disordering positions in YB56 were detected from the differential images between observed and simulated images based on x-ray data, which were B24 clusters around the Y-holes. The present work indicates that the structure analysis combined with digital high-resolution electron microscopy, electron diffraction, and differential images is useful for the evaluation of atomic positions and disordering in the boron-based crystals.


Author(s):  
Kenneth H. Downing ◽  
Robert M. Glaeser

The contrast observed in images of beam-sensitive, crystalline specimens is found to be significantly less than one would predict based on observations of electron diffraction patterns of the specimens. Factors such as finite coherence, inelastic scattering, and the limited MTF of the photographic emulsion account for some decrease in contrast. It appears, however, that most of the loss in signal is caused by motion of the specimen during exposure to the electron beam. The introduction of point and other defects in the crystal, resulting from radiation damage, causes bending and lateral motion, which degrade the contrast in the image. We have therefore sought to determine whether the beam-induced specimen motion can be reduced by reducing the area of the specimen which is illuminated at any one time.


Materials containing planar boundaries are of general interest and complete understanding of their structures is important. When direct imaging of the boundaries by, for instance, high-resolution electron microscopy, is impracticable, details of their structure and arrangement may be obtained from electron diffraction patterns. Such patterns are discussed in terms of those from intergrowth tungsten bronzes as specific examples. Fourier-transform calculations for proposed structures have been made to establish, in conjunction with optical-diffraction analogues, the features of the far-field diffraction patterns. These results have been compared with diffraction patterns obtained experimentally by transmission electron microscopy. The aim of the study, to show that the arrangement of the boundaries in these complicated phases can be deduced from their diffraction patterns without the need for high-resolution imaging, has been achieved. The steps to be taken to make these deductions are set out.


1986 ◽  
Vol 82 ◽  
Author(s):  
R.S. Rai ◽  
M.A. O'Keefe ◽  
G. Thomas

ABSTRACTHigh resolution electron microscopy has been employed to elucidate fault defects and structural details of the δ1 and δ2-Y2Si2O7 crystalline phases. From this study δ1 and δ2-Y2Si2O7 have been found to be orthorhombic having the same cell parameters but different atomic arrangements due to a change in their space groups. Computer simulations were necessary for interpreting details from the high resolution electron micrographs.


1995 ◽  
Vol 10 (6) ◽  
pp. 1539-1545 ◽  
Author(s):  
G.Z. Pan ◽  
A. Michel ◽  
V. Pierron-Bohnes ◽  
P. Vennéguès ◽  
M.C. Cadeville

Plan-view microstructures of two Co/Ru bilayers with a composition of [Co12ÅRu45Å]2 and [Co40ÅRu35Å]2 have been studied by conventional and high resolution electron microscopy. Large differences in electron diffraction and image contrast between the two bilayers were observed, which are recognized as the microstructural variations during the relaxation of large coherent planar strains when the Co layers wet coherently or semicoherently the Ru layers. For the [Co12ÅRu45Å]2 bilayer, the Co layers are unrelaxed from the Ru layers; only one set of electron diffraction patterns was observed, and the image consists of three types of contrasts which are closely related with either the generation and movement of misfit dislocations or large coherent strains. For the [Co40ÅRu35Å]2 bilayer, the Co layers are relaxed basically from the Ru layers; two sets of electron diffraction patterns with double diffraction spots were observed, and the image consists of small irregular areas with moiré fringe dots.


1987 ◽  
Vol 99 ◽  
Author(s):  
William Krakow ◽  
Thomas M. Shaw

ABSTRACTExperimental high resolution electron micrographs and computer simulation experiments have been used to evaluate the visibility of the atomic constituents of YBa2Cu3O7−x. In practice, the detection of oxygen has not been possible in contradiction to that predicted by modelling of perfect crystalline material. Preliminary computer experiments of the electron diffraction patterns when oxygen vacancies are introduced on the Cu-O sheets separating Ba layers show the diffuse streaks characteristic of short range ordering.


1999 ◽  
Vol 55 (2) ◽  
pp. 255-257 ◽  
Author(s):  
X. Y. Yang ◽  
G. Y. Shi ◽  
X. M. Meng ◽  
H. L. Huang ◽  
Y. K. Wu

Using electron diffraction patterns and high-resolution electron microscopy (HREM), a trace 114R SiC in commercial α-SiC powder (mainly 6H SiC according to X-ray diffraction) has been discovered. In a hexagonal unit cell its stacking sequence is [(33)4(34)2]3, the periodicity along the c axis is 286.14 Å and a = b = 3.073 Å. 114R belongs to the structure series of (33) n34(33) m34 predicted theoretically by Pandey & Krishna [Mater. Sci. Eng. (1975), 20, 243–249] on the basis of the faulted matrix model.


2000 ◽  
Vol 56 (3) ◽  
pp. 363-368 ◽  
Author(s):  
Takeo Oku ◽  
Anna Carlsson ◽  
Jan-Olov Bovin ◽  
Christer Svensson ◽  
L. Reine Wallenberg ◽  
...  

The modulated structure of Ag2SnO3, disilver tin trioxide, was investigated by high-resolution electron microscopy and electron diffraction along four different directions. Electron diffraction showed an incommensurate one-dimensional modulated structure with a modulation wavevector of 1/6.4a*. High-resolution images showed a large number of superstructure domains with the size range 10–100 nm and orientations related by hexagonal rotation. The modulation was determined to be displacements along the c axis of the Ag atoms both in octahedral and linear coordination. An approximate structure model with a commensurate sixfold superstructure, with an orthorhombic cell (P212121, a = 2.922, b = 1.267, c = 0.562 nm), is proposed. Calculated images and electron diffraction patterns, based on this model, agree well with experimental observations.


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