Insight from X-ray Absorption Spectroscopy to Octahedral/Tetrahedral Site Distribution in Sm-Doped Iron Oxide Magnetic Nanoparticles

2018 ◽  
Vol 122 (15) ◽  
pp. 8543-8552 ◽  
Author(s):  
M. A. Soldatov ◽  
J. Göttlicher ◽  
S. P. Kubrin ◽  
A. A. Guda ◽  
T. A. Lastovina ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Magnetic Nanoparticles ◽  
Absorption Spectroscopy ◽  
Tetrahedral Site ◽  
X Ray ◽  
Site Distribution ◽  
Iron Oxide Magnetic Nanoparticles ◽  
X Ray Absorption

X-ray absorption spectroscopy and density functional analysis of the Fe3+ distribution profile on Al sites in a chrysoberyl crystal, BeAl2O4:Fe3+

2016 ◽  
Vol 49 (2) ◽  
pp. 385-388 ◽  
Author(s):  
Kanokwan Kanchiang ◽  
Atipong Bootchanont ◽  
Janyaporn Witthayarat ◽  
Sittichain Pramchu ◽  
Panjawan Thanasuthipitak ◽  
...  
Keyword(s):  
Optical Properties ◽  
Absorption Spectroscopy ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Distribution Profile ◽  
Laser Applications ◽  
Edge Structure ◽  
X Ray ◽  
Site Distribution ◽  
X Ray Absorption

Chrysoberyl is one of the most interesting minerals for laser applications, widely used for medical purposes, as it exhibits higher laser performance than other materials. Although its utilization has been vastly expanded, the location of transition metal impurities, especially the iron that is responsible for chrysoberyl's special optical properties, is not completely understood. The full understanding and control of these optical properties necessitates knowledge of the precise location of the transition metals inside the structure. Therefore, synchrotron X-ray absorption spectroscopy (XAS), a local structural probe sensitive to the different local geometries, was employed in this work to determine the site occupation of the Fe3+ cation in the chrysoberyl structure. An Fe K-edge X-ray absorption near-edge structure (XANES) simulation was performed in combination with density functional theory calculations of Fe3+ cations located at different locations in the chrysoberyl structure. The simulated spectra were then qualitatively compared with the measured XANES features. The comparison indicates that Fe3+ is substituted on the two different Al2+ octahedral sites with the proportion 60% on the inversion site and 40% on the reflection site. The accurate site distribution of Fe3+ obtained from this work provides useful information on the doping process for improving the efficiency of chrysoberyl as a solid-state laser material.

scholarly journals Manganese incorporation in synthetic hercynite

2015 ◽  
Vol 79 (3) ◽  
pp. 635-647 ◽  
Author(s):  
G. D. Bromiley ◽  
G. D. Gatta ◽  
T. Stokes
Keyword(s):  
Single Crystal ◽  
Absorption Spectroscopy ◽  
Structure Refinement ◽  
Tetrahedral Site ◽  
Silicate Melt ◽  
X Ray ◽  
Octahedral Sites ◽  
Partial Disorder ◽  
X Ray Absorption ◽  
Preferential Incorporation

AbstractManganese incorporation in synthetic hercynite, and partitioning between hercynite and silicate melt synthesized at 1.0 GPa, 1250°C, and at an fO2 buffered by Fe–FeO, has been studied by X-ray absorption spectroscopy and single-crystal X-ray structure refinement. Spectra indicate the presence of both Mn2+ and Mn3+ (and possibly also Mn4+) in synthetic hercynite and partitioning of Mn2+ into the melt phase, and Mn3+ into hercynite, respectively, under run conditions. X-ray refinement is consistent with partial disorder of Fe and Al across tetrahedral and octahedral sites. A higher than expected degree of Fe-Al disorder in the Mn-bearing hercynite can be explained by preferential incorporation of Mn2+ onto the tetrahedral site, and indicates that Fe-Al disorder in pure, stoichiometric hercynite cannot necessarily be used to determine closure temperatures in natural spinel. However, partitioning of Mn2+ and Mn3+ between melt and hercynite suggests that Mn incorporation in hercynite could be used as a measure of fO2 conditions in magmas during spinel crystallization.

scholarly journals Monitoring of Arsenite Sorption to Biogenic Iron Oxide in a Flow-Through Column by X-Ray Absorption Spectroscopy

2015 ◽  
Vol 13 (0) ◽  
pp. 455-460
Author(s):  
Yoko Fujikawa ◽  
Masataka Sugahara ◽  
Tetsuo Honma ◽  
Sayaka Hirayama ◽  
Phan Do Hung ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Absorption Spectroscopy ◽  
X Ray ◽  
Flow Through ◽  
X Ray Absorption ◽  
Biogenic Iron

The Effect of Water on the Stability of Iron Oxide and Iron Carbide Nanoparticles in Hydrogen and Syngas Followed by in Situ X-ray Absorption Spectroscopy

2012 ◽  
Vol 116 (13) ◽  
pp. 7367-7373 ◽  
Author(s):  
Peter Thüne ◽  
Prabashini Moodley ◽  
Freek Scheijen ◽  
Hans Fredriksson ◽  
Remco Lancee ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Absorption Spectroscopy ◽  
Iron Carbide ◽  
X Ray ◽  
Effect Of Water ◽  
The Stability ◽  
X Ray Absorption

scholarly journals Fibrillar biocomposite on the base of poly(3-hydroxybutyrate) nanofibers and iron oxide magnetic nanoparticles

2019 ◽  
Vol 489 (2) ◽  
pp. 157-160
Author(s):  
V. E. Prusakov ◽  
Yu. V. Maksimov ◽  
V. A. Beglov ◽  
M. V. Gerasimov ◽  
A. V. Bychkova ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Iron Oxide ◽  
Magnetic Nanoparticles ◽  
Oxide Nanoparticles ◽  
The Novel ◽  
X Ray ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Iron Oxide Magnetic Nanoparticles

The novel biodegradable biocomposites on the base of poly(3-hydroxybutyrare) nanofibers with embedded iron oxide nanoparticles have been studied by transmission electron microscopy (TEM), Mssbayer spectroscopy, small angle X‑ray scattering (SAXS), and macroscopic magnetization techniques.

scholarly journals Identifying the Chemical Origin of Oxygen Redox Activity in Li-Rich Anti-Fluorite Lithium Iron Oxide by Experimental and Theoretical X-ray Absorption Spectroscopy

2019 ◽  
Vol 10 (4) ◽  
pp. 806-812 ◽  
Author(s):  
Liang Li ◽  
Eungje Lee ◽  
John W. Freeland ◽  
Timothy T. Fister ◽  
Michael M. Thackeray ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Absorption Spectroscopy ◽  
Redox Activity ◽  
X Ray ◽  
X Ray Absorption
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