Tc versus ΔVA correlation in Cu-oxide superconductors

1990 ◽  
Vol 165-166 ◽  
pp. 983-984 ◽  
Author(s):  
Y. Ohta ◽  
T. Tohyama ◽  
S. Maekawa
Keyword(s):  
Oxide Superconductors

The measurement of thin-film reaction layers with high-resolution FESEM

1995 ◽  
Vol 53 ◽  
pp. 330-331
Author(s):  
Paul G. Kotula ◽  
C. Barry Carter
Keyword(s):  
Thin Film ◽  
High Resolution ◽  
Reaction Layer ◽  
Product Layer ◽  
Buffer Layers ◽  
Oxide Superconductors ◽  
Rate Limiting Step ◽  
Ceramic Thin Film ◽  
Backscattered Electron ◽  
Boundary Reaction

Thin-film reactions in ceramic systems are of increasing importance as materials such as oxide superconductors and ferroelectrics are applied in thin-film form. In fact, reactions have been found to occur during the growth of YBa2Cu3O6+x on ZrO2. Additionally, thin-film reactions have also been intentionally initiated for the production of buffer layers for the subsequent growth of high-Tc superconductor thin films. The problem is that the kinetics of ceramic thin-film reactions are not well understood when the reaction layer is very thin; that is, when the rate-limiting step is a phase-boundary reaction as opposed to diffusion of the reactants through the product layer. In this case, the reaction layer is likely to be laterally non-uniform. In the present study, the measurement of thin reaction-product layers is accomplished by first digitally acquiring backscattered-electron images in a high-resolution field-emission scanning electron microscope (FESEM) followed by image analysis. Furthermore, the problem of measuring such small thicknesses (e.g., 20-500nm) over lengths of interfaces longer than 3mm is addressed.

Atomic resolution AEM (ARAEM) of oxide superconductors

1992 ◽  
Vol 50 (1) ◽  
pp. 74-75
Author(s):  
Vinayak P. Dravid ◽  
H. Zhang ◽  
L.D. Marks ◽  
J.P. Zhang
Keyword(s):  
Electron Microscope ◽  
Field Emission ◽  
Atomic Resolution ◽  
Oxide Superconductors ◽  
Electron Holography ◽  
Analytical Electron ◽  
Analytical Electron Microscope ◽  
Point To Point ◽  
Single Instrument ◽  
Better Than

A 200 kV cold field emission gun atomic resolution analytical electron microscope (ARAEM, Hitachi HF-2000) has been recently installed at Northwestern. The ARAEM offers an unprecedented combination of atomic structure imaging of better than 0.20 nm nominal point-to-point resolution and about 0.10 nm line resolution, alongwith nanoscale analytical capabilities and electron holography in one single instrument. The ARAEM has been fully functional/operational and this paper presents some illustrative examples of application of ARAEM techniques to oxide superconductors. Additional results will be presented at the meeting.

Superconducting current in hybrid heterojunctions of metal-oxide superconductors: Size and frequency dependences

2005 ◽  
Vol 101 (3) ◽  
pp. 494-503 ◽  
Author(s):  
Yu. V. Kislinskii ◽  
P. V. Komissinski ◽  
K. Y. Constantinian ◽  
G. A. Ovsyannikov ◽  
T. Yu. Karminskaya ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Oxide Superconductors ◽  
Superconducting Current ◽  
Frequency Dependences

Tc IN MULTI-LAYER OXIDE SUPERCONDUCTORS

1989 ◽  
Vol 03 (01) ◽  
pp. 109-115 ◽  
Author(s):  
RUIBAO TAO ◽  
XIAO HU ◽  
MASUO SUZUKI
Keyword(s):  
Transition Temperature ◽  
Oxide Superconductors ◽  
Nearest Neighbour ◽  
Model Hamiltonian

A possible relation of the supeconducting transition temperature T c to the number of Cu-O planes coupled tightly in a Tl-Ca-Ba-Cu-O compound is discussed by means of Anderson's RVB theory. A model Hamiltonian has been suggested to include the tunneling of singlet pairs between the nearest neighbour Cu-O planes and our calculation shows that the experimental T c can be fitted well and raised obviously by increasing the number of Cu-O planes at first, then it becomes more and more insensitive as the number is increased beyond 4 or 5. The maximum T c may approach 144 K.

NEUTRON POWDER DIFFRACTION AND OXIDE SUPERCONDUCTORS

1993 ◽  
Vol 07 (16n17) ◽  
pp. 3077-3093 ◽  
Author(s):  
A.W. HEWAT
Keyword(s):  
Heavy Metals ◽  
High Temperature ◽  
Powder Diffraction ◽  
Neutron Powder Diffraction ◽  
Oxide Superconductors ◽  
X Rays ◽  
New Materials ◽  
Oxidation Reduction ◽  
High Temperature Oxide ◽  
Temperature Oxide

Neutron powder diffraction has been essential for understanding the structures of the new high temperature oxide superconductors because of the difficulty in locating oxygen with X-rays in the presence of heavy metals, especially when single crystals are usually not available. This understanding lead to the discovery of new materials. In this paper we will show how it also sheds light on the crystal chemistry of oxide superconductors—the effects of oxidation/reduction, phase separation, pressure etc.

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