scholarly journals Statistical Mechanics Treatment of the Broadened Snoek Relaxation Peak in Ternary Niobium–Vanadium–Oxygen Alloys

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1948 ◽  
Author(s):  
Jian Ren ◽  
Liming Yu ◽  
Yongchang Liu ◽  
Huijun Li ◽  
Zongqin Ma ◽  
...  
Keyword(s):  
Statistical Mechanics ◽  
Transition Probabilities ◽  
Cell Model ◽  
Interstitial Oxygen ◽  
Octahedral Sites ◽  
Relaxation Parameters ◽  
Element Species ◽  
Site Dependence ◽  
Snoek Relaxation ◽  
Oxygen Atoms

The Snoek relaxation profiles for ternary Niobium–Vanadium–Oxygen systems were analyzed by an embedded-cell model of statistical mechanics treatment. The relaxation characteristic and broadening mechanism were systematically discussed and some conflicting interpretations in the early research were clarified. The complicated Snoek spectrums of the Nb–V–O system can be resolved into a series of effective elementary Debye peaks, which result from the transitions of interstitial oxygen atoms between adjacent octahedral sites. The relaxation parameters of each elementary peak can be determined by element species and atomic arrangements within the corresponding embedded octahedron. The Snoek relaxation characteristic in Nb–V–O systems mainly depends on the sites distributions and the transitions status of the interstitial oxygen atoms, which are controlled by the site-dependence energies and the transition probabilities, respectively.

A THEORETICAL STUDY OF POINT DEFECTS IN ZIRCONIA – SILICON INTERFACES

2006 ◽  
Vol 16 (01) ◽  
pp. 389-396
Author(s):  
Masashi Nakatomi ◽  
Koichi Yamashita
Keyword(s):  
Point Defects ◽  
Density Functional ◽  
Theoretical Study ◽  
Gate Dielectrics ◽  
Cell Model ◽  
Interstitial Oxygen ◽  
Super Cell ◽  
Defect Levels ◽  
Silicon Interface ◽  
Oxygen Atoms

We present a theoretical study on the point defects in ZrO 2–silicon interfaces using molecular dynamics (MD) calculations. A super-cell model that contains 9 atomic layers of silicon and 9 atomic layers of ZrO 2 was used for the simulation. Three atomic layers containing 17 oxygen atoms, eight silicon atoms, and nine Zr atoms were used to simulate the ZrO 2–silicon interface. We then performed density functional theory (DFT) with plane-wave basis to calculate the interface band structure. Results demonstrate that the stretched Zr – O bonds at the interface would produce some defect levels in the band gap. Particularly, the defect levels originated from the interstitial oxygen atoms are located close to the bottom of the ZrO 2 conduction band and hence it will affect the electrical properties of the gate dielectrics.

A New Type of Ordered Arrangement of Interstitial Oxygen Atoms in the a Solid Solution of the Zr-O System

1972 ◽  
Vol 32 (4) ◽  
pp. 1146-1146 ◽  
Author(s):  
Shinya Hashimoto ◽  
Hiroshi Iwasaki ◽  
Shiro Ogawa ◽  
Sadae Yamaguchi ◽  
Makoto Hirabayashi
Keyword(s):  
Solid Solution ◽  
Interstitial Oxygen ◽  
New Type ◽  
Oxygen Atoms

X-Ray Measurement of the Static Lattice Distortion in the Solid Solution of Oxygen in Titanium*

1962 ◽  
Vol 6 ◽  
pp. 136-141
Author(s):  
F. R. L. Schoening ◽  
F. Witt
Keyword(s):  
Single Crystal ◽  
Oxygen Concentration ◽  
Waller Factor ◽  
Interstitial Oxygen ◽  
Exponential Factor ◽  
X Ray ◽  
X Ray Scattering ◽  
Lattice Strains ◽  
Debye Waller Factor ◽  
Oxygen Atoms

AbstractOxygen was introduced into a single crystal of titanium in successive stages. The intensities of the h00 and 00l reflections were measured with a single-crystal diffractometer. The observed variation of the intensities with oxygen concentration was attributed to three factors: (1) the additional scattering from the oxygen atoms, (2) a change in the Debye-Waller factor, and (3) an exponential factor originating from the distortion around the oxygen atom. The theory of X-ray scattering from crystals containing centers of distortion was applied to the hexagonal titanium containing interstitial oxygen atoms. Using the variation of the lattice constant with oxygen concentration, it was possible to predict the intensity reduction due to lattice strains. It was concluded that it would have been possible to obtain an estimate of the defect concentration from the X-ray measurements of lattice expansion and intensity reduction.

scholarly journals First-Principles Calculations of Oxygen-Dislocation Interaction in Magnesium

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 116
Author(s):  
Chao Fang ◽  
Jing Zhang ◽  
Ying Huang ◽  
Jianhao Chen
Keyword(s):  
Screw Dislocation ◽  
First Principles ◽  
Dislocation Core ◽  
Prismatic Slip ◽  
Interstitial Oxygen ◽  
First Principles Calculations ◽  
Dislocation Interaction ◽  
Dislocation Glide ◽  
Deformation Behaviors ◽  
Oxygen Atoms

The interaction between interstitial oxygen atoms and <a>-type screw dislocations was investigated via first-principles calculations to elucidate the effect of oxygen solutes on the deformation behaviors of Mg. The results show that repulsive interactions exist between basal screw dislocation cores and oxygen atoms, which would enable the full basal dislocation to bypass the oxygen atoms in the dislocation glide plane through the cross-slip process. This repulsion also increases the resistance to the motion of dissociated basal dislocations. Moreover, the energy of prismatic <a>-type screw dislocation cores is reduced by the presence of oxygen, which would stabilize the screw dislocation core on the prismatic plane, accordingly facilitating the prismatic slip. This information can complement the fundamental knowledge of alloying Mg using interstitial solutes.

A TEM study of the ordering of excess interstitial oxygen atoms in Ln2NiO4+δ(Ln = La, Nd)

1992 ◽  
Vol 97 (2) ◽  
pp. 443-451 ◽  
Author(s):  
L.C. Otero-Diaz ◽  
A.R. Landa ◽  
F. Fernandez ◽  
R. Saez-Puche ◽  
R. Withers ◽  
...  
Keyword(s):  
Interstitial Oxygen ◽  
Oxygen Atoms

Ordering of interstitial oxygen atoms in La2NiO4+ delta

1991 ◽  
Vol 4 (1S) ◽  
pp. S139-S141 ◽  
Author(s):  
Z Hiroi ◽  
M Takano ◽  
Y Bando
Keyword(s):  
Interstitial Oxygen ◽  
Oxygen Atoms

First-principles study of PbWO4crystal with interstitial oxygen atoms

2007 ◽  
Vol 204 (3) ◽  
pp. 776-783 ◽  
Author(s):  
Chen Teng ◽  
Liu Ting-Yu ◽  
Zhang Qi-Ren ◽  
Li Fang-Fei ◽  
Yi Zhi-Jun ◽  
...  
Keyword(s):  
First Principles ◽  
Interstitial Oxygen ◽  
First Principles Study ◽  
Oxygen Atoms

Computer simulation of PbMoO4 crystal with interstitial oxygen atoms

2008 ◽  
Vol 41 (3) ◽  
pp. 330-333 ◽  
Author(s):  
Chen Jianyu ◽  
Zhang Qiren ◽  
Liu Tingyu ◽  
Shao Zexu ◽  
Pu Chunying
Keyword(s):  
Computer Simulation ◽  
Interstitial Oxygen ◽  
Oxygen Atoms

scholarly journals Dual Oxygen Defects in Layered La1.2Sr0.8−xBaxInO4+δ (x = 0.2, 0.3) Oxide-Ion Conductors: A Neutron Diffraction Study

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1624 ◽  
Author(s):  
Loreto Troncoso ◽  
Carlos Mariño ◽  
Mauricio D. Arce ◽  
José Antonio Alonso
Keyword(s):  
Oxygen Vacancies ◽  
Parent Compound ◽  
Layered Perovskite ◽  
Total Conductivity ◽  
Interstitial Oxygen ◽  
Ionic Conductors ◽  
Ion Conductor ◽  
Oxide Ion Conductor ◽  
Oxide Ion ◽  
Oxygen Atoms

The title compounds exhibit a K2NiF4-type layered perovskite structure; they are based on the La1.2Sr0.8InO4+δ oxide, which was found to exhibit excellent features as fast oxide-ion conductor via an interstitial oxygen mechanism. These new Ba-containing materials were designed to present a more open framework to enhance oxygen conduction. The citrate-nitrate soft-chemistry technique was used to synthesize such structural perovskite-type materials, followed by annealing in air at moderate temperatures (1150 °C). The subtleties of their crystal structures were investigated from neutron powder diffraction (NPD) data. They crystallize in the orthorhombic Pbca space group. Interstitial O3 oxygen atoms were identified by difference Fourier maps in the NaCl layer of the K2NiF4 structure. At variance with the parent compound, conspicuous oxygen vacancies were found at the O2-type oxygen atoms for x = 0.2, corresponding to the axial positions of the InO6 octahedra. The short O2–O3 distances and the absence of steric impediments suggest a dual oxygen-interstitial mechanism for oxide-ion conduction in these materials. Conductivity measurements show that the activation energy values are comparable to those typical of ionic conductors working by simple vacancy mechanisms (~1 eV). The increment of the total conductivity for x = 0.2 can be due to the mixed mechanism driving both oxygen vacancies and interstitials, which is original for these potential electrolytes for solid-oxide fuel cells.

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