A practical method of three-dimensional space-group analysis using convergent-beam electron diffraction

1975 ◽  
Vol 31 (6) ◽  
pp. 804-810 ◽  
Author(s):  
P. Goodman
Keyword(s):  
Electron Diffraction ◽  
Dimensional Space ◽  
Group Analysis ◽  
Three Dimensional ◽  
Practical Method ◽  
Convergent Beam Electron Diffraction ◽  
Beam Electron ◽  
Space Group ◽  
Convergent Beam ◽  
Three Dimensional Space

Bloch-wave interpretations of Gjønnes–Moodie lines in convergent-beam electron diffraction for non-symmorphic space-group crystals

2021 ◽  
Vol 77 (3) ◽  
pp. 222-231
Author(s):  
Hirofumi Matsuhata
Keyword(s):  
Electron Diffraction ◽  
Dimensional Space ◽  
High Energy ◽  
Bloch Wave ◽  
Convergent Beam Electron Diffraction ◽  
Bloch Waves ◽  
Beam Electron ◽  
Space Group ◽  
Space Groups ◽  
Convergent Beam

The contrast of Gjønnes–Moodie (GM) lines which appear in convergent-beam electron diffraction patterns for non-symmorphic space-group crystals is explained using Bloch waves. In the two-dimensional space groups p2mg and pg the Bloch waves for electron diffraction are described. In both space groups along the Δ line, Bloch waves are arranged as two different types, and it is shown that the two types of Bloch waves do not contribute to the intensity of forbidden reflections. Along the position where the forbidden reflection satisfies the Bragg condition, degeneracies of two Bloch waves are found and it is shown that the degenerated pair of Bloch waves do not contribute to the intensity. These Bloch-wave results provide a new perspective in the understanding of the contrast mechanism of GM lines previously described using scattering polynomials. They also advance the understanding of Bloch-wave behaviour in high-energy electron diffraction.

Determination of space group of BaPb0.75Bi0.25O3 by convergent-beam electron diffraction

2002 ◽  
Vol 382 (4) ◽  
pp. 422-430 ◽  
Author(s):  
Takuya Hashimoto ◽  
Kenji Tsuda ◽  
Junichiro Shiono ◽  
Junichiro Mizusaki ◽  
Michiyoshi Tanaka
Keyword(s):  
Electron Diffraction ◽  
Convergent Beam Electron Diffraction ◽  
Beam Electron ◽  
Space Group ◽  
Convergent Beam

Space Group Determination of the Room-Temperature Phase ofα '-NaV2O5Using Convergent-Beam Electron Diffraction

2000 ◽  
Vol 69 (7) ◽  
pp. 1939-1941 ◽  
Author(s):  
Kenji Tsuda ◽  
Shuichi Amamiya ◽  
Michiyoshi Tanaka ◽  
Yukio Noda ◽  
Masahiko Isobe ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Room Temperature ◽  
Convergent Beam Electron Diffraction ◽  
Temperature Phase ◽  
Beam Electron ◽  
Space Group ◽  
Convergent Beam

Identification of the impurity phase in high-purity CeB6 by convergent-beam electron diffraction

2019 ◽  
Vol 75 (3) ◽  
pp. 489-500
Author(s):  
Ding Peng ◽  
Philip N. H. Nakashima
Keyword(s):  
Electron Diffraction ◽  
High Purity ◽  
Density Functional ◽  
Convergent Beam Electron Diffraction ◽  
Impurity Phase ◽  
Lattice Parameters ◽  
Beam Electron ◽  
Space Group ◽  
Convergent Beam ◽  
Very High

The rare earth hexaborides are known for their tendency towards very high crystal perfection. They can be grown into large single crystals of very high purity by inert gas arc floating zone refinement. The authors have found that single-crystal cerium hexaboride grown in this manner contains a significant number of inclusions of an impurity phase that interrupts the otherwise single crystallinity of this prominent cathode material. An iterative approach is used to unequivocally determine the space group and the lattice parameters of the impurity phase based on geometries of convergent-beam electron diffraction (CBED) patterns and the symmetry elements that they possess in their intensity distributions. It is found that the impurity phase has a tetragonal unit cell with space group P4/mbm and lattice parameters a = b = 7.23 ± 0.03 and c = 4.09 ± 0.02 Å. These agree very well with those of a known material, CeB4. Confirmation that this is indeed the identity of the impurity phase is provided by quantitative CBED (QCBED) where the very close match between experimental and calculated CBED patterns has confirmed the atomic structure. Further confirmation is provided by a density functional theory calculation and also by high-angle annular dark-field scanning transmission electron microscopy.

Space Group Determination of Decagonal Quasicrystals of an Al70Ni15Fe15Alloy Using Convergent-Beam Electron Diffraction

1992 ◽  
Vol 31 (Part 2, No. 2A) ◽  
pp. L109-L112 ◽  
Author(s):  
Masakazu Saito ◽  
Michiyoshi Tanaka ◽  
An Pang Tsai ◽  
Akihisa Inoue ◽  
Tsuyoshi Masumoto
Keyword(s):  
Electron Diffraction ◽  
Convergent Beam Electron Diffraction ◽  
Beam Electron ◽  
Space Group ◽  
Decagonal Quasicrystals ◽  
Convergent Beam

scholarly journals SPACE GROUP DETERMINATION OF Li2O·3Nb2O5 BY CONVERGENT BEAM ELECTRON DIFFRACTION

1984 ◽  
Vol 33 (11) ◽  
pp. 1586
Author(s):  
YANG CUI-YING ◽  
FENG GUO-GANG ◽  
ZHOU YU-QING ◽  
TANG DI-SHENG
Keyword(s):  
Electron Diffraction ◽  
Convergent Beam Electron Diffraction ◽  
Beam Electron ◽  
Space Group ◽  
Convergent Beam

Thickness dependence of the intensities of the 200 forbidden reflections in the TiBe2 diamond type structure

1988 ◽  
Vol 46 ◽  
pp. 826-827
Author(s):  
Dang-Rong Liu ◽  
D. B. Williams
Keyword(s):  
Electron Diffraction ◽  
Diffraction Pattern ◽  
Convergent Beam Electron Diffraction ◽  
Type Structure ◽  
Beam Electron ◽  
Space Group ◽  
X Ray ◽  
Electron Diffraction Technique ◽  
Convergent Beam ◽  
Diamond Type

It is interesting to note that for the diamond type structure of Si, Ge and diamond, the forbidden {200} reflections in the exact <100> orientation diffraction pattern cannot be seen. In contrast, we also note a standing controversy over the structure of the MgAl2O4, spinel. Its structure was determined long ago by x-ray powder method as Fd3m (the diamond type). However, its electron diffraction pattern taken in the <100> orientation shows weak {200} reflections, which are taken as evidence that the spinel should have the space group F43m (the blende type), rather than Fd3m. Others speculate that these {200} reflections result from the high order Laue zone (HOLZ) reflections, and the spinel should be Fd3m. Nevertheless, still others think that these analyses are not conclusive. We have carefully studied the space group of TiBe2 using the convergent beam electron diffraction technique, and unambiguously demonstrated that its space group must be Fd3m.

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