scholarly journals Study the oxygen vacancies and Fe oxidation states in CaFeO3-δ perovskite nanomaterial

2022 ◽  
Vol 624 ◽  
pp. 413415
Author(s):  
E.K. Abdel-Khalek ◽  
M.A. Motawea ◽  
Mohamed A. Aboelnasr ◽  
H.H. El-Bahnasawy
Keyword(s):  
Oxygen Vacancies ◽  
Oxidation States ◽  
Fe Oxidation

scholarly journals Study the Oxygen Vacancies and Fe Oxidation States in CaFeO3-δ Perovskite Nanomaterial

2021 ◽  
Author(s):  
eid khalaf ◽  
E. K. Abdel-Khalek ◽  
M. A. Motawea ◽  
Mohamed A. Aboelnasr ◽  
H. H. El-Bahnasawy
Keyword(s):  
Mössbauer Spectroscopy ◽  
Photoelectron Spectroscopy ◽  
Oxygen Vacancies ◽  
Mossbauer Spectroscopy ◽  
Oxidation States ◽  
Differential Scanning Calorimetric ◽  
X Ray ◽  
Mößbauer Spectroscopy ◽  
Fe Oxidation ◽  
Fe Ions

Abstract In this study, CaFeO3-δ perovskite nanomaterial has been synthesized by sol-gel method. The oxygen vacancies and Fe oxidation states in CaFeO3-δ perovskite nanomaterial were investigated by using X-ray diffraction (XRD), Mössbauer spectroscopy, X-ray photoelectron spectroscopy (XPS), thermogravimetry analysis (TG), differential scanning calorimetric (DSC), and vibrating sample magnetometer (VSM). Rietveld analysis of the XRD shows that the sample was crystallized in orthorhombic perovskite structure with space group pcmn. The oxygen vacancies and oxidation states of Fe ions in CaFeO3-δ sample were determined from Mössbauer spectroscopy. XPS shows the presence of different states of Fe ions and oxygen vacancies in the surface of CaFeO3-δ sample. The thermal and magnetic properties of this sample have been investigated.

A STRUCTURAL CHEMICAL MODEL FOR HIGH Tc CERAMIC SUPERCONDUCTORS

1987 ◽  
Vol 01 (07n08) ◽  
pp. 275-288 ◽  
Author(s):  
S.R. OVSHINSKY ◽  
S.J. HUDGENS ◽  
R.L. LINTVEDT ◽  
D.B. RORABACHER
Keyword(s):  
Electronic Properties ◽  
Oxygen Vacancies ◽  
Oxygen Removal ◽  
Bose Condensation ◽  
Oxidation States ◽  
Chemical Model ◽  
Electrically Conductive ◽  
High Tc ◽  
Ceramic Superconductors ◽  
Mixed Oxidation

A structual chemical model for high Tc ceramic superconductors is proposed in which carriers pairs, coupled through a superexchange process, undergo Bose condensation. In the Y-Ba-Cu-O system, Cu atoms on “chain” sites and “sheet” sites are initially assigned formal oxidation states of +3 and +2, respectively, and “sheet”/“chain” interactions are then introduced to bring about the electrically conductive mixed oxidation state. This model explains the presence of labile oxygen in the “chain” structures, describes the structure of deoxygenated phases exhibiting ordered oxygen vacancies in the “chains”, and allows interpretation of the effects of oxygen removal on magnetic and electronic properties of the material.

The determination of Ti, Mn and Fe oxidation states in minerals by electron energy-loss spectroscopy

1985 ◽  
Vol 18 (1-4) ◽  
pp. 285-289 ◽  
Author(s):  
Max T. Otten ◽  
Barbara Miner ◽  
James H. Rask ◽  
Peter R. Buseck
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Oxidation States ◽  
Fe Oxidation ◽  
Electron Energy Loss

scholarly journals Ultra-High and Near-Zero Refractive Indices of Magnetron Sputtered Thin-Film Metamaterials Based on TixOy

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Vukoman Jokanović ◽  
Božana Čolović ◽  
Miloš Nenadović ◽  
Anka Trajkovska Petkoska ◽  
Miodrag Mitrić ◽  
...  
Keyword(s):  
Oxygen Vacancies ◽  
Band Gaps ◽  
Oxidation States ◽  
Refractive Indices ◽  
Dc Magnetron Sputtering ◽  
High Concentration ◽  
Extinction Coefficients ◽  
Electron Transitions ◽  
Titanium Oxidation ◽  
Very High

Metamaterials based onTixOywith ultra-high and near-zero refractive indices were obtained by DC magnetron sputtering. The data on refractive indices, extinction coefficients, film thickness, and band gaps, obtained by spectroscopic ellipsometry, showed very high potential of these materials as metamaterials. Phase analysis performed by XRD revealed the presence of titanium phases with lower titanium oxidation states resulting from high concentration of oxygen vacancies, which are crucial for such extraordinary jumps and drops of refractive indices. Numerous band gaps for direct and indirect electron transitions additionally confirmed unique properties of these materials.

scholarly journals Synthesis, structure and magnetic behavior of iron arsenites with hierarchical magnetic units

2020 ◽  
Vol 7 (20) ◽  
pp. 3987-3999
Author(s):  
Bastien Leclercq ◽  
Houria Kabbour ◽  
Angel M. Arevalo-Lopez ◽  
Sylvie Daviero-Minaud ◽  
Claire Minaud ◽  
...  
Keyword(s):  
Magnetic Behavior ◽  
Oxidation States ◽  
Fe Oxidation

Iron-arsenites may cover multiple Fe oxidation states, while the versatile (AsO3)2− condensation offer ideal spacers between magnetic sub-units with various dimensionalities (D). We show here four novel compounds covering the 0–3D magnetic panorama.

On the Role of Oxidation States in the Electronic Structure via the Formation of Oxygen Vacancies of a Doped MoVTeNbOx in Propylene Oxidation

2021 ◽  
pp. 151428
Author(s):  
J. Ramírez-Salgado ◽  
R. Quintana-Solórzano ◽  
Isidro Mejía-Centeno ◽  
H. Armendáriz-Herrera ◽  
A. Rodríguez-Hernández ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Oxygen Vacancies ◽  
Oxidation States ◽  
Propylene Oxidation

scholarly journals Reversal magnetization dependence with the Cr and Fe oxidation states in YFe1−Cr O3 (0≤x≤1) perovskites

2016 ◽  
Vol 408 ◽  
pp. 94-98 ◽  
Author(s):  
F.A. Fabian ◽  
P.P. Pedra ◽  
K.O. Moura ◽  
J.G.S. Duque ◽  
C.T. Meneses
Keyword(s):  
Oxidation States ◽  
Fe Oxidation ◽  
Magnetization Dependence

scholarly journals Selenium Valence-to-Core X-ray Emission Spectroscopy and Kβ HERFD X-ray Absorption Spectroscopy as Complementary Probes of Chemical and Electronic Structure

2021 ◽  
Author(s):  
Justin T. Henthorn ◽  
Serena DeBeer
Keyword(s):  
Absorption Spectroscopy ◽  
Emission Spectroscopy ◽  
Active Sites ◽  
Structural Information ◽  
Oxidation States ◽  
Geochemical Processes ◽  
X Ray ◽  
Fe Oxidation ◽  
Experimental Resolution ◽  
X Ray Absorption

Selenium X-ray absorption spectroscopy (XAS) has found widespread use in investigations of Se-containing materials, geochemical processes, and biological active sites. In contrast to sulfur Kβ X-ray emission spectroscopy (XES), which has been found to contain electronic and structural information complementary to S XAS, Se Kβ XES remains comparatively under-explored. Herein, we present the first Se Valence-to-Core (VtC) XES studies of reduced Se-containing compounds and FeSe dimers. Se VtC XES is found to be sensitive to changes in covalent Se bonding interactions (Se–Se/Se–C/Se–H bonding) while relatively insensitive to changes in Fe oxidation states as selenide bridges in FeSe dimers ([Fe2Se2]2+ vs [Fe2Se2]+). Contrastingly, Se Kβ HERFD XAS is demonstrated to be quite sensitive to changes in Fe-oxidation state, with Se Kβ HERFD XAS demonstrating experimental resolution equivalent to K𝛼 HERFD XAS. Additionally, computational studies reveal both Se VtC XES and XAS to be sensitive to selenium protonation in FeSe complexes.

Sign in / Sign up

Export Citation Format

Share Document