scholarly journals Electron Diffraction Study of the Space Group Variation in the Al–Mn–Pt T-Phase

Symmetry ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 38
Author(s):  
Rimon Tamari ◽  
Benjamin Grushko ◽  
Louisa Meshi
Keyword(s):  
High Temperature ◽  
Electron Diffraction ◽  
Diffraction Study ◽  
Electron Diffraction Study ◽  
Ternary Systems ◽  
Homogeneity Region ◽  
Space Group ◽  
Space Groups ◽  
Group Variation ◽  
T Phase

Binary high temperature “Al3Mn” (T-phase) and its extensions in ternary systems were the subjects of numerous crystallographic investigations. The results were ambiguous regarding the existence or lack of the center of symmetry: both Pna21 and Pnam space groups were reported. Our research on the Al–Mn–Pt T-phase allowed concluding that inside a continuous homogeneity region, the structure of the Al-rich T-phase (e.g., Al78Mn17.5Pt4.5) belongs to the non-centrosymmetric Pna21 space group, while the structure of the Al-poor T-phase (such as Al71.3Mn25.1Pt3.6) is centrosymmetric, i.e., Pnam. Following metallurgical and crystallographic considerations, the change in the symmetry was explained.

Electron diffraction study of a high-temperature diamond-like silicon ferromagnet with the self-organized superlattice distribution of manganese impurity

JETP Letters ◽  
2015 ◽  
Vol 100 (11) ◽  
pp. 719-723 ◽  
Author(s):  
E. S. Demidov ◽  
V. V. Podol’skii ◽  
V. P. Lesnikov ◽  
E. D. Pavlova ◽  
A. I. Bobrov ◽  
...  
Keyword(s):  
High Temperature ◽  
Electron Diffraction ◽  
Diffraction Study ◽  
Electron Diffraction Study ◽  
The Self ◽  
Self Organized

CONVERGENT BEAM ELECTRON DIFFRACTION STUDY OF Bi-BASED HIGH TEMPERATURE SUPERCONDUCTING LAYERED COMPOUNDS

1990 ◽  
Vol 04 (09) ◽  
pp. 605-611 ◽  
Author(s):  
X. F. ZHANG ◽  
Y. F. YAN ◽  
K. K. FUNG
Keyword(s):  
High Temperature ◽  
Electron Diffraction ◽  
Diffraction Study ◽  
Wave Vector ◽  
Electron Diffraction Study ◽  
Convergent Beam Electron Diffraction ◽  
Stacking Fault ◽  
Layered Compounds ◽  
Beam Electron ◽  
Convergent Beam

Cleaved specimens of layered compounds Bi 2 Sr 2( CaCuO 2)n CuO 6, n = 0, 1 and 2 phases have been studied by convergent beam electron diffraction. The identity and the symmetry of the phases have been determined from the higher order Laue zone (HOLZ) rings and the symmetry of their [001] patterns. In the case of Bi 2 Sr 2 CuO 6, the [001] axial periodicity corresponds to the component of the wave vector of the monoclinic modulation along the c axis. Widely different axial periodicities have been obtained. This is interpreted as the manifestation of the variation of the monoclinic modulation. The presence of basal stacking fault lowers the symmetry of the [001] pattern.

Electron diffraction study of the space group of Bi5Ti3FeO15 multiferroic ceramic

2020 ◽  
Vol 76 (5) ◽  
pp. 454-457
Author(s):  
Ying Zheng ◽  
Xinyan Wu ◽  
Yongcheng Zhang ◽  
Weiquan Shao ◽  
Wanneng Ye
Keyword(s):  
Electron Diffraction ◽  
Room Temperature ◽  
Electron Diffraction Study ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Space Groups ◽  
Phase Compound ◽  
First Time

Bi5Ti3FeO15 (pentabismuth trititanium iron pentadecaoxide), which is a multiferroic four-layer Aurivillius phase compound, has received much attention in recent years. However, three mutually inconsistent orthorhombic space groups, i.e. A21 am, Fmm2 and Pnn2, have been reported for the room-temperature phase of Bi5Ti3FeO15 by X-ray and neutron diffraction investigations. Here, electron diffraction results are presented and discussed for the first time to unambiguously clarify the room-temperature space group of ceramic Bi5Ti3FeO15. It has been found that all the observed reflections from the ceramic agree with those expected in A21 am, while the observed reflections 011, 013 and 015 should be forbidden in the case of Fmm2, and no 107 and 109 reflections were observed although allowed for Pnn2. The present study has demonstrated that the space group of Bi5Ti3FeO15 ceramic is A21 am rather than Fmm2 or Pnn2, an identification that proved to be a challenge for X-ray diffraction. On the basis of the space group A21 am, the lattice parameters of the Bi5Ti3FeO15 ceramic were calculated from its X-ray diffraction data.

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