Valence State of Ru at the Mn Sites in Pr0.5Sr0.5MnO3

2003 ◽  
Vol 17 (18n20) ◽  
pp. 3745-3748 ◽  
Author(s):  
B. H. Kim ◽  
J. S. Kim ◽  
D. C. Kim ◽  
Y. W. Park ◽  
A. Maignan ◽  
...  
Keyword(s):  
Valence State ◽  
Carrier Density ◽  
Magnetic Interactions ◽  
Charge Carrier Density ◽  
Edge Structure ◽  
X Ray ◽  
Ru Doping ◽  
X Ray Absorption ◽  
Tetravalent State

Valence state of the doped Ru at the Mn sites in Pr 0.5 Sr 0.5 MnO 3 has been studied using Ru K-edge X-ray absorption near-edge structure (XANES) spectroscopy. In comparison with XANES of reference ruthenates, it is found that the Mn-site doped Ru is dominantly in tetravalent state. This result suggests that the change of charge carrier density by Ru doping is not sufficient to understand drastic enhancement of ferromagnetism observed in the transport properties of Ru-doped Pr 0.5 Sr 0.5 MnO 3. The prime role of Ru in Mn 3+– O – Mn 4+ networks is discussed in terms of the valency effect and the magnetic interactions between doped Ru and Mn ions.

Valence State of Ru at the Mn Sites in Pr0.5Sr0.5MnO3: Thermoelectric Power and X-Ray Absorption Near-Edge Structure Spectroscopy

2004 ◽  
Vol 17 (2) ◽  
pp. 183-186 ◽  
Author(s):  
J. S. Kim ◽  
B. H. Kim ◽  
D. C. Kim ◽  
H. J. Lee ◽  
M. G. Kim ◽  
...  
Keyword(s):  
Thermoelectric Power ◽  
Valence State ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

scholarly journals Synchrotron-Based Nano-XANES Reveals Intracellular Heterogeneity of Iron Species in Magnetotactic Bacteria

2021 ◽  
Author(s):  
Daniel Chevrier ◽  
Elisa Cerdá-Doñate ◽  
Yeseul Park ◽  
Fernando Cacho-Nerin ◽  
Miguel Gomez-Gonzalez ◽  
...  
Keyword(s):  
Cell Level ◽  
Iron Species ◽  
Intracellular Iron ◽  
Iron Storage ◽  
Edge Structure ◽  
X Ray ◽  
Magnetite Biomineralization ◽  
Iron Material ◽  
X Ray Absorption

<p>This report demonstrates how scanning X-ray fluorescence microscopy (SXFM) and nanoscale X-ray absorption near-edge structure (nano-XANES) can spatially and chemically identify intracellular iron species at the single-cell level, creating an opportunity to examine the role of iron storage in magnetite biomineralization. Fe K-edge nano-XANES measurements of <i>Magnetospirillum gryphiswaldense</i> in varied iron media conditions and iron storage capacity revealed intracellular iron heterogeneities through a distinction between formed magnetosomes and intracellular iron material. This work highlights the potential of nano-XANES in providing an experimental advantage in the multidisciplinary field of biomineralization.</p>

ELECTRONIC STRUCTURES OF La0.7Ca0.3MnO3 AND La0.7Ce0.3MnO3 BY X-RAY ABSORPTION SPECTROSCOPY

2002 ◽  
Vol 09 (02) ◽  
pp. 1053-1057 ◽  
Author(s):  
K. ASOKAN ◽  
K. V. R. RAO ◽  
J. C. JAN ◽  
J. W. CHIOU ◽  
W. F. PONG ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Electronic Structures ◽  
Spectral Features ◽  
Electron Hole ◽  
Edge Structure ◽  
X Ray ◽  
Strong Hybridization ◽  
Doped Manganites ◽  
X Ray Absorption ◽  
Tetravalent State

Electronic structures of hole-doped and electron hole-doped manganites, La 0.7 Ca 0.3 MnO 3 and La 0.7 Ce 0.3 MnO 3, have been elucidated by X-ray absorption near-edge structure (XANES) spectra of O K- and Mn L3,2-edges. In the electron-doped system, La 0.7 Ce 0.3 MnO 3, the spectral features of O K-edge spectra are shifted by ~ 1 eV towards the higher energy side and reduction of Mn valency from 4+ and 3+ to 3+ and 2+ is expected when compared to hole-doped manganite. The XANES of Ce M5,4-edges indicates a tetravalent state for Ce, similar to that in CeO 2. Ce 4+ is incorporated into the lattice of LaMnO 3, resulting in the modification of MnO 6 octahedra and also indicating strong hybridization of Ce 5d and/or Ce 4f states with O 2p states.

Adsorption and oxidation of SO2 on the surface of TiO2 nanoparticles: the role of terminal hydroxyl and oxygen vacancy–Ti3+ states

2020 ◽  
Vol 22 (18) ◽  
pp. 9943-9953
Author(s):  
Bing Wang ◽  
Xue Li ◽  
Shanshan Liang ◽  
Runxuan Chu ◽  
Dan Zhang ◽  
...  
Keyword(s):  
High Resolution ◽  
Oxygen Vacancy ◽  
Tio2 Nanoparticles ◽  
Photoelectron Spectroscopy ◽  
Flow Chamber ◽  
Oxidation Reactions ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

The absorption and oxidation reactions of SO2 on TiO2 nanoparticles were investigated by using a flow chamber, synchrotron X-ray absorption near-edge structure and high resolution synchrotron X-ray photoelectron spectroscopy techniques.

X-ray absorption near-edge structure and valence state of Mn in (Ga,Mn)N

2005 ◽  
Vol 72 (11) ◽  
Author(s):  
A. Titov ◽  
X. Biquard ◽  
D. Halley ◽  
S. Kuroda ◽  
E. Bellet-Amalric ◽  
...  
Keyword(s):  
Valence State ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

scholarly journals SYNCHROTRON BASED MICRO-MAPPING AND XAFS INVESTIGATION OF Fe-Mn AND EPIGENETIC INTERGROWTH WITHIN THE CAMBRIAN SHALLOW MANGANESE DEPOSITS, SOUTH JORDAN

2020 ◽  
Vol 53 (1A) ◽  
pp. 117-127
Author(s):  
Tayel El-Hasa
Keyword(s):  
Ore Deposits ◽  
Manganese Ore ◽  
Elemental Distribution ◽  
Ore Formation ◽  
Edge Structure ◽  
X Ray ◽  
Atomic Structures ◽  
X Ray Absorption ◽  
Wadi Araba

The current work investigates the Cambrian Manganese ore deposits from Wadi Dana at central Wadi Araba region. This investigation aims to unravel the chemistry and micro-textures of the mineral paragenetic sequence for these manganese ore deposits. Particularly the Fe–Mn intimate intergrowth micro texture and the epigenetic Mn mineralization associated with Cu minerals. The combination of the synchrotron-based X-ray fluorescence (syn-XRF) micro-mapping and X-ray absorption fine structure (XAFS) techniques were used. They provide a clear picture of the elemental distribution of Mn, Fe, Cu, and Pb and other elements presented within the ore micro textures. Besides, it determines the exact elemental speciation. The results obtained gave a better understanding of the elemental atomic structures and eventually the depositional environment. Particularly, the syn-XRF micro-mapping reveals the existing of many successive evolution stages in the Mn ores. Besides, the X-ray Absorption Near Edge Structure (XANES) results showed that the micro-rhythmic texture is changing from Mn+4 (Pyrolusite) into Fe+3 (Hematite). This is evidence for the role of Eh as the main controlling factor during the ore formation. Eventually, indicating tentatively the paleoceanography setting of the Mn deposits. This is related to the continuous transgression-regression on the sea level in a semi-closed sea.

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