Convergent-beam characterization of some oxides which undergo structural phase transformations

1987 ◽  
Vol 45 ◽  
pp. 20-23
Author(s):  
M. Tanaka
Keyword(s):  
Phase Transformations ◽  
Room Temperature ◽  
Materials Science ◽  
Present Report ◽  
Structural Phase ◽  
Crystal Defects ◽  
Temperature Phase ◽  
Space Group ◽  
Convergent Beam ◽  
Structural Phase Transformations

We have been concerned with the development of convergent-beam electron diffraction (CBED) techniques and their application to materials science. Our effort is now concentrated to identify the nature of crystal defects. Our application has been focussed on materials most of which undergo structural phase transformations: NdNbO4, La2Ti2O7, Sr2(Ta1-xNbx)2O7, Fe3O4, PbZrO3, PbZrO0-7Ti0.3O3, SrTiO3, BaPb1-xBixO3, hex.BaTiO3, Bi2.5Na0.5Nb2O9, MgAl2O4, MnSi, TaS3, NbS3+x, Mo2S3. In the present report, the results on four oxides will be reviewed.a) La2Ti2O7Gasperin determined the space group of the room temperature phase to be P21, but Scheunemann and Miüller-Buschbaum reported its space group to be Pna21. Ishizawa et al. studied the phase transformation between room temperature and 1173 K using X-ray diffraction. They determined the space group of the room temperature phase to be P21 and found the presence of twin domains.

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

Betaine arsenate, (CH3)3NCH2COO · D3AsO4: structure refinement using multiple-wavelength synchrotron radiation data

1997 ◽  
Vol 212 (9) ◽  
Author(s):  
S. Kek ◽  
M. Grotepaß-Deuter ◽  
K. Fischer ◽  
K. Eichhorn
Keyword(s):  
Crystal Structure ◽  
Synchrotron Radiation ◽  
Room Temperature ◽  
Structure Refinement ◽  
Temperature Phase ◽  
Space Group ◽  
Radiation Data ◽  
Multiple Wavelength

AbstractThe crystal structure of deuterated betaine arsenate, (CHThe both paraelectric and ferroelastic room-temperature phase of betaine arsenate crystallizes in space group

scholarly journals Structural phase transformations in annealed Pt/Mn/Fe trilayers

2020 ◽  
Vol 32 (36) ◽  
pp. 365404
Author(s):  
I O Kruhlov ◽  
O V Shamis ◽  
N Y Schmidt ◽  
M V Karpets ◽  
S Gulyas ◽  
...  
Keyword(s):  
Phase Transformations ◽  
Structural Phase ◽  
Structural Phase Transformations

Pressure-Induced Structural Phase Transformations in Silicon Nanowires

2005 ◽  
Vol 5 (5) ◽  
pp. 729-732 ◽  
Author(s):  
H. K. Poswal ◽  
Nandini Garg ◽  
Surinder M. Sharma ◽  
E. Busetto ◽  
S. K. Sikka ◽  
...  
Keyword(s):  
Phase Transformations ◽  
Silicon Nanowires ◽  
Structural Phase ◽  
Structural Phase Transformations

The structures and phase transitions in 4-aminopyridinium tetraaquabis(sulfato)iron(III), (C5H7N2)[FeIII(H2O)4(SO4)2]

2019 ◽  
Vol 75 (6) ◽  
pp. 1144-1151
Author(s):  
Tamara J. Bednarchuk ◽  
Wolfgang Hornfeck ◽  
Vasyl Kinzhybalo ◽  
Zhengyang Zhou ◽  
Michal Dušek ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Single Crystal ◽  
Room Temperature ◽  
Variable Temperature ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Hybrid Compound ◽  
Space Group ◽  
X Ray

The organic–inorganic hybrid compound 4-aminopyridinium tetraaquabis(sulfato)iron(III), (C5H7N2)[FeIII(H2O)4(SO4)2] (4apFeS), was obtained by slow evaporation of the solvent at room temperature and characterized by single-crystal X-ray diffraction in the temperature range from 290 to 80 K. Differential scanning calorimetry revealed that the title compound undergoes a sequence of three reversible phase transitions, which has been verified by variable-temperature X-ray diffraction analysis during cooling–heating cycles over the temperature ranges 290–100–290 K. In the room-temperature phase (I), space group C2/c, oxygen atoms from the closest Fe-atom environment (octahedral) were disordered over two equivalent positions around a twofold axis. Two intermediate phases (II), (III) were solved and refined as incommensurately modulated structures, employing the superspace formalism applied to single-crystal X-ray diffraction data. Both structures can be described in the (3+1)-dimensional monoclinic X2/c(α,0,γ)0s superspace group (where X is ½, ½, 0, ½) with modulation wavevectors q = (0.2943, 0, 0.5640) and q = (0.3366, 0, 0.5544) for phases (II) and (III), respectively. The completely ordered low-temperature phase (IV) was refined with the twinning model in the triclinic P{\overline 1} space group, revealing the existence of two domains. The dynamics of the disordered anionic substructure in the 4apFeS crystal seems to play an essential role in the phase transition mechanisms. The discrete organic moieties were found to be fully ordered even at room temperature.

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