scholarly journals Oxygen Potentials and Defect Chemistry in Nonstoichiometric (U,Pu)O2

10.5772/33672 ◽  
2012 ◽  
Author(s):  
Masato Kato
Keyword(s):  
Defect Chemistry

Dislocations, Ordering and Antiferromagnetic Domains in MnO

1970 ◽  
Vol 28 ◽  
pp. 522-523
Author(s):  
D. J. Barber ◽  
R. G. Evans
Keyword(s):  
Electron Diffraction ◽  
Single Crystal ◽  
Optical Microscopy ◽  
Defect Chemistry ◽  
Magnetic Structures ◽  
Optically Transparent ◽  
Magnetic Features ◽  
Antiferromagnetic Domains

Manganese (II) oxide, MnO, in common with CoO, NiO and FeO, possesses the NaCl structure and shows antiferromagnetism below its Neel point, Tn∼ 122 K. However, the defect chemistry of the four oxides is different and the magnetic structures are not identical. The non-stoichiometry in MnO2 small (∼2%) and below the Tn the spins lie in (111) planes. Previous work reported observations of magnetic features in CoO and NiO. The aim of our work was to find explanations for certain resonance results on antiferromagnetic MnO.Foils of single crystal MnO were prepared from shaped discs by dissolution in a mixture of HCl and HNO3. Optical microscopy revealed that the etch-pitted foils contained cruciform-shaped precipitates, often thick and proud of the surface but red-colored when optically transparent (MnO is green). Electron diffraction and probe microanalysis indicated that the precipitates were Mn2O3, in contrast with recent findings of Co3O4 in CoO.

The impact of metal ions doping on the defect chemistry of methylammonium lead iodide

2018 ◽  
Author(s):  
Nga Phung ◽  
Antonio Abate ◽  
Daniele Meggiolaro ◽  
Filippo De Angelis ◽  
Roberto Felix Duarte ◽  
...  
Keyword(s):  
Metal Ions ◽  
Defect Chemistry ◽  
Lead Iodide ◽  
Methylammonium Lead Iodide ◽  
The Impact

scholarly journals Is Reduced Strontium Titanate a Semiconductor or a Metal?

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 744
Author(s):  
Christian Rodenbücher ◽  
Christo Guguschev ◽  
Carsten Korte ◽  
Sebastian Bette ◽  
Kristof Szot
Keyword(s):  
Point Defect ◽  
Decisive Role ◽  
Thermal Reduction ◽  
Defect Chemistry ◽  
Oxygen Activity ◽  
Metallic State ◽  
Metallic Behavior ◽  
Reducing Conditions ◽  
History Play ◽  
Semiconducting Behavior

In recent decades, the behavior of SrTiO3 upon annealing in reducing conditions has been under intense academic scrutiny. Classically, its conductivity can be described using point defect chemistry and predicting n-type or p-type semiconducting behavior depending on oxygen activity. In contrast, many examples of metallic behavior induced by thermal reduction have recently appeared in the literature, challenging this established understanding. In this study, we aim to resolve this contradiction by demonstrating that an initially insulating, as-received SrTiO3 single crystal can indeed be reduced to a metallic state, and is even stable against room temperature reoxidation. However, once the sample has been oxidized at a high temperature, subsequent reduction can no longer be used to induce metallic behavior, but semiconducting behavior in agreement with the predictions of point defect chemistry is observed. Our results indicate that the dislocation-rich surface layer plays a decisive role and that its local chemical composition can be changed depending on annealing conditions. This reveals that the prediction of the macroscopic electronic properties of SrTiO3 is a highly complex task, and not only the current temperature and oxygen activity but also the redox history play an important role.

Opening catalytic sites in the copper-triazoles framework via defect chemistry for switching on the proton reduction

2021 ◽  
pp. 119941
Author(s):  
Zhao-Di Wang ◽  
Ying Zang ◽  
Zhi-Juan Liu ◽  
Peng Peng ◽  
Rui Wang ◽  
...  
Keyword(s):  
Defect Chemistry ◽  
Proton Reduction ◽  
Catalytic Sites

SrZn2N2 as a Solar Absorber: Theoretical Defect Chemistry and Synthesis by Metal Alloy Nitridation

2021 ◽  
Author(s):  
Ryosuke Kikuchi ◽  
Koki Ueno ◽  
Toru Nakamura ◽  
Takahiro Kurabuchi ◽  
Yasushi Kaneko ◽  
...  
Keyword(s):  
Defect Chemistry ◽  
Metal Alloy ◽  
Solar Absorber

scholarly journals Linker depletion for missing cluster defects in non-UiO Metal-Organic Frameworks

2021 ◽  
Author(s):  
Isabel Abánades Lázaro ◽  
Neyvis Almora-Barrios ◽  
Sergio Tatay ◽  
Catalin Popescu ◽  
Carlos Martí-Gastaldo
Keyword(s):  
Metal Organic Frameworks ◽  
Defect Chemistry ◽  
Defect Engineering ◽  
Preferential Formation ◽  
Metal Organic

Defect engineering is a valuable tool to tune the properties of Metal-Organic Frameworks. However, defect chemistry remains still predominantly limited to UiO-type MOFs. We describe the preferential formation of missing...

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