The local structure of 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 from neutron total scattering measurements and multi-edge X-ray absorption analysis

2021 ◽  
Vol 135 ◽  
pp. 111124
Author(s):  
Charles McLouth Culbertson ◽  
Alicia Manjón-Sanz ◽  
Marcos Lucero ◽  
Zhenxing Feng ◽  
Michelle R. Dolgos
Keyword(s):  
Local Structure ◽  
Absorption Analysis ◽  
Total Scattering ◽  
X Ray ◽  
Scattering Measurements ◽  
X Ray Absorption ◽  
Neutron Total Scattering

Local Structure of Ba1–xSrxTiO3and BaTi1–yZryO3Nanocrystals Probed by X-ray Absorption and X-ray Total Scattering

ACS Nano ◽  
2013 ◽  
Vol 7 (12) ◽  
pp. 11435-11444 ◽  
Author(s):  
Federico A. Rabuffetti ◽  
Richard L. Brutchey
Keyword(s):  
Local Structure ◽  
Total Scattering ◽  
X Ray ◽  
X Ray Absorption

Total scattering studies of silica polymorphs: similarities in glass and disordered crystalline local structure

2000 ◽  
Vol 64 (3) ◽  
pp. 447-457 ◽  
Author(s):  
D. A. Keen ◽  
M. T. Dove
Keyword(s):  
Local Structure ◽  
Glass Structure ◽  
Quantitative Comparison ◽  
Crystalline Phases ◽  
Total Scattering ◽  
Disordered Structure ◽  
Scattering Measurements ◽  
Crystalline Forms ◽  
Short Range Correlations ◽  
Neutron Total Scattering

AbstractThe structure of amorphous silica has frequently been compared with its crystalline counterparts in an attempt to understand the glass structure beyond short-range correlations. This paper presents results from neutron total scattering measurements of several polymorphs of silica and shows how these can be used to make a direct, quantitative comparison of amorphous and crystalline forms. It is found that the glass is similar to HP-tridymite and β-cristobalite, both dynamically-disordered crystalline phases of silica, but only out to distances ∼7.5 Å, beyond which the structures diverge. This is too small to validate a microcrystallite theory of glass structure. It is the average 180° Si–O–Si linkage in these two crystalline phases which gives them the flexibility for their instantaneous disordered structure to resemble the quenched (static) glass structure.

Local structure and oxidation state of uranium in some ternary oxides: X-ray absorption analysis

2007 ◽  
Vol 180 (1) ◽  
pp. 54-61 ◽  
Author(s):  
A.V. Soldatov ◽  
D. Lamoen ◽  
M.J. Konstantinović ◽  
S. Van den Berghe ◽  
A.C. Scheinost ◽  
...  
Keyword(s):  
Oxidation State ◽  
Local Structure ◽  
Absorption Analysis ◽  
X Ray ◽  
X Ray Absorption ◽  
Ternary Oxides

scholarly journals A combined fit of total scattering and extended X-ray absorption fine structure data for local-structure determination in crystalline materials

2009 ◽  
Vol 42 (5) ◽  
pp. 867-877 ◽  
Author(s):  
V. Krayzman ◽  
I. Levin ◽  
J. C. Woicik ◽  
Th. Proffen ◽  
T. A. Vanderah ◽  
...  
Keyword(s):  
Fine Structure ◽  
Multiple Scattering ◽  
Structure Determination ◽  
Local Structure ◽  
Group Symmetry ◽  
Total Scattering ◽  
Exafs Data ◽  
X Ray ◽  
Absorption Fine ◽  
X Ray Absorption

Reverse Monte Carlo (RMC) refinements of local structure using a simultaneous fit of X-ray/neutron total scattering and extended X-ray absorption fine structure (EXAFS) data were developed to incorporate an explicit treatment of both single- and multiple-scattering contributions to EXAFS. The refinement algorithm, implemented as an extension to the public domain computer softwareRMCProfile, enables accurate modeling of EXAFS over distances encompassing several coordination shells around the absorbing species. The approach was first tested on Ni, which exhibits extensive multiple scattering in EXAFS, and then applied to perovskite-like SrAl1/2Nb1/2O3. This compound crystallizes with a cubic double-perovskite structure but presents a challenge for local-structure determination using a total pair-distribution function (PDF) alone because of overlapping peaks of the constituent partial PDFs (e.g.Al—O and Nb—O or Sr—O and O—O). The results obtained here suggest that the combined use of the total scattering and EXAFS data provides sufficient constraints for RMC refinements to recover fine details of local structure in complex perovskites. Among other results, it was found that the probability density distribution for Sr in SrAl1/2Nb1/2O3adoptsTdpoint-group symmetry for the Sr sites, determined by the ordered arrangement of Al and Nb, as opposed to a spherical distribution commonly assumed in traditional Rietveld refinements.

The Ba3Mo1−xWxNbO8.5 ion conductors: insights into local coordination from X-ray and neutron total scattering

2020 ◽  
Vol 8 (40) ◽  
pp. 21227-21240
Author(s):  
Mauro Coduri ◽  
Andrea Bernasconi ◽  
Henry E. Fischer ◽  
Lorenzo Malavasi
Keyword(s):  
Phase Transition ◽  
High Temperature ◽  
Local Structure ◽  
Total Scattering ◽  
X Ray ◽  
Local Coordination ◽  
Octahedral Sites ◽  
Neutron Total Scattering ◽  
Ion Conductors

The local structure of Ba3Mo1−xWxNbO8.5 is consistent with a mixture of regions richer in tetrahedral and octahedral sites, which redistribute at high temperature after a reconstructive phase transition.

X-Ray Absorption Analysis of Ge and Ga Environments in Ba-Gallogermante Glasses

1993 ◽  
Vol 307 ◽  
Author(s):  
Celia I. Merzbacher ◽  
David A. McKeown
Keyword(s):  
Bond Length ◽  
Absorption Spectroscopy ◽  
Local Structure ◽  
Octahedral Coordination ◽  
Absorption Analysis ◽  
Tetrahedral Coordination ◽  
X Ray ◽  
X Ray Absorption ◽  
Absorption Edges

ABSTRACTX-ray absorption spectroscopy has been used to characterize the local structure surrounding Ga and Ge in BaO-Ga2O3-GeO2 glasses. Based on comparisons with results for crystalline standards of known structure, Ge and Ga in all of the glasses are primarily in tetrahedral coordination; no evidence for octahedral coordination is observed. Bond length and coordination values derived from fitting calculations are fairly uniform for all glasses, however disorder increases with increase in BaO and decrease in GeO2 content, especially in the second shell surrounding Ge and Ga. Ge absorption edges for all glasses resemble smoothed BGG-An or GeO2 [quartz] edges. Ga absorption edges of the glasses also resemble the BGG-An edge which has two edge maxima, but in the glasses the relative intensities of the two maxima vary with composition.

Application of In Situ X-ray Absorption Spectroscopy to Study Dilute Chromium Ions in a Molten Chloride Salt

2019 ◽  
Author(s):  
Jisue Moon ◽  
Carter Abney ◽  
Dmitriy Dolzhnikov ◽  
James M. Kurley ◽  
Kevin A. Beyer ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Local Structure ◽  
Chloride Salt ◽  
X Ray ◽  
Molten Chloride ◽  
Stable Species ◽  
Higher Temperature ◽  
Cr Concentration ◽  
X Ray Absorption

The local structure of dilute CrCl<sub>3</sub> in a molten MgCl<sub>2</sub>:KCl salt was investigated by <i>in situ</i> x-ray absorption spectroscopy (XAS) at temperatures from room temperature to 800<sup>o</sup>C. This constitutes the first experiment where dilute Cr speciation is explored in a molten chloride salt, ostensibly due to the compounding challenges arising from a low Cr concentration in a matrix of heavy absorbers at extreme temperatures. CrCl<sub>3</sub> was confirmed to be the stable species between 200 and 500<sup>o</sup>C, while mobility of metal ions at higher temperature (>700<sup>o</sup>C) prevented confirmation of the local structure.

scholarly journals Local Structure and Dynamics of Functional Materials Studied by X-ray Absorption Fine Structure

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1315
Author(s):  
Takafumi Miyanaga
Keyword(s):  
Fine Structure ◽  
Local Structure ◽  
Chemical Reactivity ◽  
Functional Materials ◽  
X Ray ◽  
Structure And Dynamics ◽  
Absorption Fine ◽  
Structure Phase Transition ◽  
Local Electronic Structure ◽  
X Ray Absorption

X-ray absorption fine structure (XAFS) is a powerful technique used to analyze a local electronic structure, local atomic structure, and structural dynamics. In this review, I present examples of XAFS that apply to the local structure and dynamics of functional materials: (1) structure phase transition in perovskite PbTiO3 and magnetic FeRhPd alloys; (2) nano-scaled fluctuations related to their magnetic properties in Ni–Mn alloys and Fe/Cr thin films; and (3) the Debye–Waller factors related to the chemical reactivity for catalysis in polyanions and ligand exchange reaction. This study shows that the local structure and dynamics are related to the characteristic function of the materials.

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