Compound-tunable embedding potential: which oxidation state of uranium and thorium as point defects in xenotime is favorable?

2020 ◽  
Vol 22 (32) ◽  
pp. 17922-17931 ◽  
Author(s):  
Yuriy V. Lomachuk ◽  
Daniil A. Maltsev ◽  
Nikolai S. Mosyagin ◽  
Leonid V. Skripnikov ◽  
Roman V. Bogdanov ◽  
...  
Keyword(s):  
Oxidation State ◽  
Point Defects ◽  
Cluster Model ◽  
Uranium Ion ◽  
Ion Impurity

The cluster model of xenotime YPO4 is provided to determine the properties of thorium and uranium ion impurity in the crystal.

Probing the oxidation state and coordination geometry of uranium ion in SrZrO3 perovskite

2014 ◽  
Vol 1068 ◽  
pp. 204-209 ◽  
Author(s):  
Santosh K. Gupta ◽  
Nimai Pathak ◽  
Ruma Gupta ◽  
S.K. Thulasidas ◽  
V. Natarajan
Keyword(s):  
Oxidation State ◽  
Coordination Geometry ◽  
Uranium Ion

Point defects in covalent semiconductors: A molecular cluster model

2009 ◽  
Vol 16 (S13) ◽  
pp. 349-361
Author(s):  
A. Fazzio ◽  
M. J. Caldas ◽  
J. R. Leite
Keyword(s):  
Point Defects ◽  
Cluster Model ◽  
Molecular Cluster

scholarly journals Point defects and oxidation state of additives in rare-earth metal doped crystals of lead telluride PbTe:Ln

2011 ◽  
Vol 4 (1/2) ◽  
pp. 160-165
Author(s):  
Dmytro FREIK ◽  
◽  
Liliya TUROVSKA ◽  
Volodymyra BOYCHUK ◽  
◽  
...  
Keyword(s):  
Rare Earth ◽  
Oxidation State ◽  
Point Defects ◽  
Rare Earth Metal ◽  
Lead Telluride ◽  
Earth Metal ◽  
Metal Doped

Bulk and Surface Electronic Properties of Oxide Dielectrics

1999 ◽  
Vol 567 ◽  
Author(s):  
Victor E. Henrich
Keyword(s):  
Dipole Moment ◽  
Metal Oxide ◽  
Electronic Properties ◽  
Oxidation State ◽  
Point Defects ◽  
Theoretical Models ◽  
Oxide Surfaces ◽  
Metal Oxide Surfaces ◽  
Surface Dipole ◽  
High Dielectric

ABSTRACTThe electronic properties of oxides that are candidates for high-dielectric insulators in ULSI are discussed. The theoretical models that can be used to describe them are compared, and the properties of cation oxidation state and point defects associated with non-stoichiometry in the bulk and on the surface are considered. Metal-oxide surfaces often reconstruct, with the creation of a surface dipole moment The effect of overlayers on metal-oxide surfaces is also discussed.

Cluster model for the electronics structure of point defects in SmS compounds

1982 ◽  
Vol 29 (1-3) ◽  
pp. 169-174 ◽  
Author(s):  
Y. Hammoud ◽  
M.A. Khan ◽  
C. Demangeat ◽  
J.C. Parlebas
Keyword(s):  
Point Defects ◽  
Cluster Model

Microstructural Evolution in Reduced TiO2

1981 ◽  
Vol 39 ◽  
pp. 74-75
Author(s):  
W. T. Donlon ◽  
S. Shinozaki ◽  
E. M. Logothetis ◽  
W. Kaizer
Keyword(s):  
Microstructural Evolution ◽  
Point Defects ◽  
Extended Defects ◽  
Small Deviations ◽  
Controlled Atmospheres ◽  
Limited Solubility ◽  
Thin Foils ◽  
Heat Treated ◽  
Porous Polycrystalline ◽  
Crystallographic Shear

Since point defects have a limited solubility in the rutile (TiO2) lattice, small deviations from stoichiometry are known to produce crystallographic shear (CS) planes which accomodate local variations in composition. The material used in this study was porous polycrystalline TiO2 (60% dense), in the form of 3mm. diameter disks, 1mm thick. Samples were mechanically polished, ion-milled by conventional techniques, and initially examined with the use of a Siemens EM102. The electron transparent thin foils were then heat-treated under controlled atmospheres of CO/CO2 and H2 and reexamined in the same manner.The “as-received” material contained mostly TiO2 grains (∼5μm diameter) which had no extended defects. Several grains however, aid exhibit a structure similar to micro-twinned grains observed in reduced rutile. Lattice fringe images (Fig. 1) of these grains reveal that the adjoining layers are not simply twin related variants of a single TinO2n-1 compound. Rather these layers (100 - 250 Å wide) are alternately comprised of stoichiometric TiO2 (rutile) and reduced TiO2 in the form of Ti8O15, with the Ti8O15 layers on either side of the TiO2 being twin related.

Simulated Dark-Field Electron Micrographs of Point Defects and Organometallics

1975 ◽  
Vol 33 ◽  
pp. 200-201
Author(s):  
William Krakow
Keyword(s):  
Electron Micrographs ◽  
Point Defects ◽  
Structure Determination ◽  
Atomic Structure ◽  
Image Interpretation ◽  
Dark Field ◽  
Field Electron ◽  
Dark Field Microscopy ◽  
Dark Field Electron

Tilted beam dark-field microscopy has been applied to atomic structure determination in perfect crystals, several synthesized molecules with heavy atcm markers and in the study of displaced atoms in crystals. Interpretation of this information in terms of atom positions and atom correlations is not straightforward. Therefore, calculated dark-field images can be an invaluable aid in image interpretation.

Defects in Crystals

1968 ◽  
Vol 26 ◽  
pp. 244-245
Author(s):  
Kenneth R. Lawless
Keyword(s):  
Electron Microscope ◽  
Point Defects ◽  
Surface Defects ◽  
Chemical Properties ◽  
Material Point ◽  
Crystal Defects ◽  
Defects In Crystals ◽  
Irradiation Effects ◽  
Normal Lattice ◽  
Line Defects

One of the most important applications of the electron microscope in recent years has been to the observation of defects in crystals. Replica techniques have been widely utilized for many years for the observation of surface defects, but more recently the most striking use of the electron microscope has been for the direct observation of internal defects in crystals, utilizing the transmission of electrons through thin samples.Defects in crystals may be classified basically as point defects, line defects, and planar defects, all of which play an important role in determining the physical or chemical properties of a material. Point defects are of two types, either vacancies where individual atoms are missing from lattice sites, or interstitials where an atom is situated in between normal lattice sites. The so-called point defects most commonly observed are actually aggregates of either vacancies or interstitials. Details of crystal defects of this type are considered in the special session on “Irradiation Effects in Materials” and will not be considered in detail in this session.

Study of dislocation loops in Arsenic-Rich as-grown GaAs

1987 ◽  
Vol 45 ◽  
pp. 350-351
Author(s):  
Byung-Teak Lee
Keyword(s):  
Point Defects ◽  
Electronic Devices ◽  
Arsenic Concentration ◽  
Stoichiometric Compound ◽  
Dislocation Loops ◽  
Gaas Crystal ◽  
Ion Milling ◽  
Transmission Electron ◽  
Arsenic Source ◽  
High Arsenic

Grown-in dislocations in GaAs have been a major obstacle in utilizing this material for the potential electronic devices. Although it has been proposed in many reports that supersaturation of point defects can generate dislocation loops in growing crystals and can be a main formation mechanism of grown-in dislocations, there are very few reports on either the observation or the structural analysis of the stoichiometry-generated loops. In this work, dislocation loops in an arsenic-rich GaAs crystal have been studied by transmission electron microscopy.The single crystal with high arsenic concentration was grown using the Horizontal Bridgman method. The arsenic source temperature during the crystal growth was about 630°C whereas 617±1°C is normally believed to be optimum one to grow a stoichiometric compound. Samples with various orientations were prepared either by chemical thinning or ion milling and examined in both a JEOL JEM 200CX and a Siemens Elmiskop 102.

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