Electronic Properties of some Ternary and Quaternary Oxides of the VIII B and I B Transition Elements: Application to High Tc Superconductivity

1989 ◽  
Vol 156 ◽  
Author(s):  
M. Pouchard ◽  
J-C. Grenier ◽  
J-P. Doumerc ◽  
G. Demazeau ◽  
J-P. Chaminade ◽  
...  
Keyword(s):  
Electronic Properties ◽  
Structural Parameters ◽  
Mixed Valence ◽  
Oxidation States ◽  
Transition Elements ◽  
High Tc Superconductors ◽  
High Tc ◽  
Electronic Configurations ◽  
Spin Electronic ◽  
Mixed Valence Compounds

ABSTRACTIn the scope of the Goodenough model, a brief review of the electronic properties of some 3d transition elements (M = Fe, Co, Ni and Cu ) is given; the main relevant electronic and structural parameters are emphasized. Then a special attention is focussed on N/(N−1) and N/(N−2) electron mixed valence compounds.Finally some particular features of copper are discussed and their relevance to high Tc superconductors is pointed out:-the srong covalency of Cu-O bondings involving a possible delocalization of the hole between trivalent copper and oxygen,-the existence of low and high spin electronic configurations for CuIII,-the disproportionation of Cu2+ and its role in the formation of hole pairs,Cu-O distances very close for the three successive oxidation states of copper favouring the disproportionation process.

Modifying electronic properties of interfaces in high-Tc superconductors by doping

1999 ◽  
Vol 326-327 ◽  
pp. 7-11 ◽  
Author(s):  
H. Hilgenkamp ◽  
C.W. Schneider ◽  
R.R. Schulz ◽  
B. Goetz ◽  
A. Schmehl ◽  
...  
Keyword(s):  
Electronic Properties ◽  
High Tc Superconductors ◽  
High Tc

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.

43Ca NMR Study of Bismuth-Based High-Tc Superconductors

1994 ◽  
Vol 49 (1-2) ◽  
pp. 373-378 ◽  
Author(s):  
A. Trokiner ◽  
L. Le Noc ◽  
A. Yakubovskii ◽  
K.N. Mykhalyov ◽  
S.V. Verkhovskii
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Electronic Properties ◽  
High Tc Superconductors ◽  
High Tc ◽  
Structural Assignment ◽  
Bismuth Compounds ◽  
Nmr Study

Abstract As a first step of a study of the electronic properties of CuO2 planes by probing calcium nuclei in the bismuth-based high-Tc materials we report here the structural assignment of Ca NMR lines measured in 43Ca-enriched samples of n = 2 ((Bi,Pb)2Sr2CaCu2O8+x) and n = 3 ((Bi,Pb)2Sr2-Ca2Cu3O10+x) bismuth compounds. Powdered samples were investigated as well as oriented pow­ ders, achieved by uniaxial alignment of the grains in a 7T magnetic field. For the main calcium site (Ca between two CuO2 planes), we could determine the quadrupolar as well as the shift tensors. The results indicate that, in the same way as yttrium nuclei in YBaCuO, calcium nuclei are sensitive to the magnetic susceptibility of the metallic CuO2 planes.

scholarly journals Oxidation States of Binary Oxides from Data Analytics of the Electronic Structure

2018 ◽  
Author(s):  
Sergei Posysaev ◽  
Olga Miroshnichenko ◽  
Matti Alatalo ◽  
Duy Le ◽  
Talat S. Rahman
Keyword(s):  
Machine Learning ◽  
Electronic Structure ◽  
Linear Regression ◽  
Data Analytics ◽  
Learning Algorithm ◽  
Mixed Valence ◽  
Oxidation States ◽  
Machine Learning Algorithm ◽  
Binary Oxides ◽  
Mixed Valence Compounds

<p>A connection between the oxidation state (OS) and Bader charge has been missing so far. To our knowledge, all previous work tried to connect OS with Bader charges only with few compounds. The aim of this work was to find a dependency between OS and Bader charge, using <a>a large number of compounds from an open database</a>. We show that a <a>correlation indeed exists between OSs and Bader charges</a> using the simplest machine learning algorithm, linear regression. The applicability of determining OS by Bader charges in mixed-valence compounds and surfaces is considered.</p>

Electron Transfer Process in Mixed Valence Compounds with Low‐lying Energy Bridge in Different Oxidation States

2020 ◽  
Author(s):  
Yu-Ying Yang ◽  
Xiao-Quan Zhu ◽  
Jean-Pierre Launay ◽  
Cheng-Bin Hong ◽  
Shao-Dong Su ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Transfer Process ◽  
Mixed Valence ◽  
Oxidation States ◽  
Electron Transfer Process ◽  
Mixed Valence Compounds

scholarly journals Oxidation States of Binary Oxides from Data Analytics of the Electronic Structure

2018 ◽  
Author(s):  
Sergei Posysaev ◽  
Olga Miroshnichenko ◽  
Matti Alatalo ◽  
Duy Le ◽  
Talat S. Rahman
Keyword(s):  
Machine Learning ◽  
Electronic Structure ◽  
Linear Regression ◽  
Data Analytics ◽  
Learning Algorithm ◽  
Mixed Valence ◽  
Oxidation States ◽  
Machine Learning Algorithm ◽  
Binary Oxides ◽  
Mixed Valence Compounds

<p>A connection between the oxidation state (OS) and Bader charge has been missing so far. To our knowledge, all previous work tried to connect OS with Bader charges only with few compounds. The aim of this work was to find a dependency between OS and Bader charge, using <a>a large number of compounds from an open database</a>. We show that a <a>correlation indeed exists between OSs and Bader charges</a> using the simplest machine learning algorithm, linear regression. The applicability of determining OS by Bader charges in mixed-valence compounds and surfaces is considered.</p>

Mixed-valence copper oxides: A large family of high Tc superconductors related to the perovskites

1989 ◽  
Vol 33 (2) ◽  
pp. 109-121 ◽  
Author(s):  
C. Michel ◽  
M. Hervieu ◽  
J. Provost ◽  
B. Raveau
Keyword(s):  
Mixed Valence ◽  
Large Family ◽  
Copper Oxides ◽  
High Tc Superconductors ◽  
High Tc
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