Cation distributions and possible phase separation inTl2Ba2CuO6+δfrom synchrotron powder x-ray diffraction

1995 ◽  
Vol 51 (18) ◽  
pp. 12747-12753 ◽  
Author(s):  
M. A. G. Aranda ◽  
D. C. Sinclair ◽  
J. P. Attfield ◽  
A. P. Mackenzie
Keyword(s):  
Phase Separation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cation Distributions

scholarly journals The phase diagram of a mixed halide (Br, I) hybrid perovskite obtained by synchrotron X-ray diffraction

RSC Advances ◽  
2019 ◽  
Vol 9 (20) ◽  
pp. 11151-11159 ◽  
Author(s):  
Frederike Lehmann ◽  
Alexandra Franz ◽  
Daniel M. Többens ◽  
Sergej Levcenco ◽  
Thomas Unold ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Solid Solution ◽  
Phase Separation ◽  
Structural Changes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hybrid Perovskite

The phase diagram elucidates structural changes and phase separation effects, induced by halide substitution in hybrid perovskite MAPb(I,Br)3 solid solution.

In situ high temperature X-ray diffraction study of the kinetics of phase separation in the uranium-plutonium mixed oxide (U0.55Pu0.45)O2-x

2014 ◽  
Vol 1645 ◽  
Author(s):  
Romain VAUCHY ◽  
Renaud.C. BELIN ◽  
Anne-Charlotte ROBISSON ◽  
Fiqiri HODAJ
Keyword(s):  
Phase Separation ◽  
Room Temperature ◽  
Mixed Oxides ◽  
Oxygen Stoichiometry ◽  
X Ray Diffraction ◽  
Fundamental Interest ◽  
X Ray ◽  
Uranium Plutonium ◽  
Kinetics Of

ABSTRACTUranium-plutonium mixed oxides incorporating high amounts of plutonium are considered for future nuclear reactors. For plutonium content higher than 20%, a phase separation occurs, depending on the temperature and on the oxygen stoichiometry. This phase separation phenomenon is still not precisely described, especially at high plutonium content. Here, using an original in situ fast X-ray diffraction device dedicated to radioactive materials, we evidenced a phase separation occurring during rapid cooling from 1773 K to room temperature at the rate of 0.05 and 2 K per second for a (U0.55Pu0.45)O2-x compound under a reducing atmosphere. The results show that the cooling rate does not impact the lattice parameters of the obtained phases at room temperature but their fraction. In addition to their obvious fundamental interest, these results are of utmost importance in the prospect of using uranium-plutonium mixed oxides with high plutonium content as nuclear fuels.

scholarly journals Vacancy-induced nanoscale phase separation in KxFe2−ySe2single crystals evidenced by Raman scattering and powder x-ray diffraction

2012 ◽  
Vol 86 (5) ◽  
Author(s):  
N. Lazarević ◽  
M. Abeykoon ◽  
P. W. Stephens ◽  
Hechang Lei ◽  
E. S. Bozin ◽  
...  
Keyword(s):  
Phase Separation ◽  
Raman Scattering ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nanoscale Phase Separation

scholarly journals Phase Separation Inside the CdTe−CdSe Type II Quantum Dots Revealed by Synchrotron X-ray Diffraction and Scattering

2008 ◽  
Vol 112 (26) ◽  
pp. 9617-9622 ◽  
Author(s):  
Hwo-Shuenn Sheu ◽  
U-Ser Jeng ◽  
Wei-Ju Shih ◽  
Ying-Huang Lai ◽  
Chiu-Hun Su ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Phase Separation ◽  
Type Ii ◽  
X Ray Diffraction ◽  
X Ray

Cross-Sectional TEM Study Of Phase Separation In Reaction Of Ni-Ta Films With GaAs

1985 ◽  
Vol 54 ◽  
Author(s):  
A. Lahav ◽  
M. Eizenberg ◽  
Y. Komem
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Transmission Electron Microscopy ◽  
Phase Separation ◽  
Gaas Substrate ◽  
Auger Spectroscopy ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
X Ray ◽  
Transmission Electron

ABSTRACTThe reaction between Ni60Ta40 amorphous alloy and (001) GaAs was studied by cross-sectional transmission electron microscopy, Auger spectroscopy, and x-ray diffraction. At 400°C formation of Ni GaAs at the interface with GaAs was observed. After heat treatment at 600°C in vacuum a layered structure of TaAs/NiGa/GaAs has been formed. The NiGa layer has epitaxial relations to the GaAs substrate. The vertical phase separation can be explained by opposite diffusion directions of nickel and arsenic atoms.

Detection and Analysis of Phase Separation in Metalorganic Chemical Vapor Deposition InGaN

1997 ◽  
Vol 482 ◽  
Author(s):  
E. L. Piner ◽  
N. A. El-Masry ◽  
S. X. Liu ◽  
S. M. Bedair
Keyword(s):  
Chemical Vapor Deposition ◽  
Phase Separation ◽  
Vapor Deposition ◽  
Metalorganic Chemical Vapor Deposition ◽  
Single Phase ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Metalorganic Chemical

AbstractInGaN films in the 0–50% InN composition range have been analyzed for the occurrence of phase separation. The ñ0.5 jum thick InGaN films were grown by metalorganic chemical vapor deposition (MOCVD) in the 690 to 780°C temperature range and analyzed by θ−20 x-ray diffraction (XRD), transmission electron microscopy (TEM), and selected area diffraction (SAD). As-grown films with up to 21% InN were single phase. However, for films with 28% InN and higher, the samples showed a spinodally decomposed microstructure as confirmed by TEM and extra spots in SAD patterns that corresponded to multiphase InGaN. An explanation of the data based on the GaN-InN pseudo-binary phase diagram is discussed.

Phase Separation in InGaN/GaN Multiple Quantum Wells

1997 ◽  
Vol 482 ◽  
Author(s):  
M. D. Mccluskey ◽  
L. T. Romano ◽  
B. S. Krusor ◽  
D. P. Bour ◽  
C. Chua ◽  
...  
Keyword(s):  
Phase Separation ◽  
Active Region ◽  
Quantum Wells ◽  
Broad Peak ◽  
Multiple Quantum Wells ◽  
Multiple Quantum ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Peaks

AbstractEvidence is presented for phase separation in In0.27Ga0.73N/GaN multiple quantum wells (MQW's). After annealing for 4 min at a temperature of 1100 °C, the absorption threshold at 2.95 eV is replaced by a broad peak at 2.65 eV. This peak is attributed to the formation of Inrich InGaN phases in the active region. X-ray diffraction measurements show a shift in the diffraction peaks toward GaN, consistent with the formation of an In-poor phase.

Crystallization of a SiO2-MgO-Al2O3-K2O-Fe2O3-F Glass

2007 ◽  
Vol 336-338 ◽  
pp. 1829-1832 ◽  
Author(s):  
Qing Bo Tian ◽  
Yue Wang ◽  
Xue Tao Yue ◽  
Yan Sheng Yin ◽  
Su Hua Fan
Keyword(s):  
Phase Separation ◽  
Electron Probe ◽  
X Ray Diffraction ◽  
Crystalline Phases ◽  
Present Glass ◽  
X Ray ◽  
Heat Treated ◽  
Mica Crystal ◽  
Step Heat Treatment ◽  
Scanning Electron

The phase-separation and the crystallization of SiO2-MgO-Al2O3-K2O-Fe2O3-F glass were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron probe of microanalyzers (EPMA). The results reveal that the varieties and the morphology of crystalline phases formed depend sensitively on the thermal treatment schedules. During the isothermal treatments, the crystalline phases of mica, mica and iron oxide (FeFeO4), and FeFeO4 as major crystals are precipitated in the glass samples heat-treated at 900, 1000 and 1050°C respectively. However, the two-step heat treatment beginning at 900°C for 1h and subsequently followed at 1050°C for 1h leads to the precipitation of mica crystal and no any signs of FeFeO4 crystalline phase is observed. Also the morphology of sample is different from that of the isothermally treated glass at 1050°C, but is similar from that of sample at 900°C. A “worm”-shaped phase-separation is observed in the sample heated at 800°C for 0.5h, which exhibits different morphology from that of droplet- or globule-shape conventionally discerned. EPMA results show that the incorporation of Fe2O3 accelerates accumulation of fluorine element, promoting the phase-separation and the crystallization of the present glass.

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