Space group and chemical analysis of Y2BaCuO5−xby convergent beam electron diffraction and x‐ray energy‐dispersive spectroscopy

1987 ◽  
Vol 51 (13) ◽  
pp. 1035-1037 ◽  
Author(s):  
John F. Mansfield ◽  
Sopa Chevacharoenkul ◽  
Angus I. Kingon
Keyword(s):  
Electron Diffraction ◽  
Chemical Analysis ◽  
Energy Dispersive Spectroscopy ◽  
Convergent Beam Electron Diffraction ◽  
Energy Dispersive ◽  
Beam Electron ◽  
Space Group ◽  
X Ray ◽  
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.

Determination of fluctuations in local symmetry and measurement by convergent beam electron diffraction: applications to a relaxor-based ferroelectric crystal after thermal annealing

2013 ◽  
Vol 46 (5) ◽  
pp. 1331-1337 ◽  
Author(s):  
Kyou-Hyun Kim ◽  
David A. Payne ◽  
Jian Min Zuo
Keyword(s):  
Electron Diffraction ◽  
Local Symmetry ◽  
Convergent Beam Electron Diffraction ◽  
Energy Dispersive ◽  
Ferroelectric Crystal ◽  
Beam Electron ◽  
X Ray ◽  
Domain Structures ◽  
Probe Size ◽  
Convergent Beam

Single crystals of Pb(Mg1/3Nb2/3)O3–31%PbTiO3(PMN–31%PT) are known for their complex domain structures at the nanometre scale. While their average symmetry has been studied by X-ray, neutron and electron diffraction methods, there is little knowledge about variations in symmetry at the local scale. Here, direct evidence is provided for the volume dependence and spatial dependence of symmetry fluctuations by using quantitative convergent beam electron diffraction and energy dispersive X-ray spectroscopy. Fluctuations in symmetry were determined by using different electron beam probe sizes ranging from ∼2 to 25 nm from a crystal ∼62 nm thick. The symmetry of PMN–31%PT was found to increase linearly as the average volume increased, and the local symmetry fluctuated from one location to another at the nanoscale. Energy dispersive X-ray spectroscopy indicates that chemical fluctuations are significant when the probe size decreases to ∼2 nm. The symmetry fluctuation is attributed to locally varying composition-dependent ionic displacements and spontaneous polarization.

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
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