Effect of oxygen redistribution in Bi-based high-Tc superconductors on their normal and superconducting properties

2000 ◽  
Vol 337 (1-4) ◽  
pp. 327-330 ◽  
Author(s):  
A.I Romanenko ◽  
L.P Kozeeva ◽  
C Dong ◽  
F Zhou ◽  
F Wu ◽  
...  
Keyword(s):  
Superconducting Properties ◽  
High Tc Superconductors ◽  
High Tc ◽  
Effect Of Oxygen

APPLICATION OF ESR TO HIGH-Tc SUPERCONDUCTORS AND RELATED MATERIALS IV: ALKALI K DOPING EFFECTS ON THE SUPERCONDUCTING CHARACTERISTICS OF K3C60

1999 ◽  
Vol 13 (02) ◽  
pp. 59-69
Author(s):  
K. SUGAWARA ◽  
N. OHYA ◽  
N. ARAI ◽  
S. ICHIMURA ◽  
K. YAMAMOTO ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Calcination Temperature ◽  
Volume Fraction ◽  
Superconducting Properties ◽  
High Tc Superconductors ◽  
High Tc ◽  
Doping Effects ◽  
Superconducting Volume Fraction ◽  
Vortex Size ◽  
Quartz Tubes

Several samples of K 3 C 60 have been made by the calcination of C 60 powder plus K flakes in evacuated quartz tubes at temperatures between 100°C and 700°C for 24 hours. The non-resonant microwave absorption (NRMA) measurements have been done below T c for these samples. From the linewidths and intensities of the NRMA signals, the superconducting properties (T c superconducting volume fraction and vortex size) have been studied as a function of the calcination temperature.

scholarly journals Orbital Symmetry and Orbital Excitations in High-Tc Superconductors

2019 ◽  
Vol 4 (2) ◽  
pp. 46 ◽  
Author(s):  
Andrzej M. Oleś ◽  
Krzysztof Wohlfeld ◽  
Giniyat Khaliullin
Keyword(s):  
Simplified Model ◽  
Entangled States ◽  
Cooper Pairing ◽  
Superconducting Properties ◽  
High Tc Superconductors ◽  
Orbital Symmetry ◽  
Spin Orbital ◽  
High Tc ◽  
High Energies

We discuss a few possibilities of high- T c superconductivity with more than one orbital symmetry contributing to the pairing. First, we show that the high energies of orbital excitations in various cuprates suggest a simplified model with a single orbital of x 2 − y 2 symmetry doped by holes. Next, several routes towards involving both e g orbital symmetries for doped holes are discussed: (i) some give superconductivity in a CuO 2 monolayer on Bi2212 superconductors, Sr 2 CuO 4 − δ , Ba 2 CuO 4 − δ , while (ii) others as nickelate heterostructures or Eu 2 − x Sr x NiO 4 , could in principle realize it as well. At low electron filling of Ru ions, spin-orbital entangled states of t 2 g symmetry contribute in Sr 2 RuO 4 . Finally, electrons with both t 2 g and e g orbital symmetries contribute to the superconducting properties and nematicity of Fe-based superconductors, pnictides or FeSe. Some of them provide examples of orbital-selective Cooper pairing.

Structural and Superconducting Properties of RE1 - 2xPrxCaxSr0.8Ba1.2Cu3O7 - δ (RE = Er and Gd) High Tc Superconductors

2003 ◽  
Vol 17 (13) ◽  
pp. 2609-2622 ◽  
Author(s):  
N. Charoenthai ◽  
P. Winotai ◽  
R. Suryanarayanan ◽  
I. M. Tang
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Transition Temperature ◽  
Size Effect ◽  
High Temperature Superconductors ◽  
Superconducting Properties ◽  
High Tc Superconductors ◽  
High Tc ◽  
Oxygen Annealing ◽  
Ion Size

We report here on the structural and superconducting properties of RE 1 - 2x Pr x Ca x Sr 0.8 Ba 1.2 Cu 3 O 7 - δ (RE = Er and Gd, 0 ≤ x ≤ 0.2) high temperature superconductors. The transition temperature (Tc) of these compounds decreases when the Pr and Ca concentrations are increased. At constant Pr and Ca concentrations, the Tc of Er 1 - 2x Pr x Ca x Sr 0.8 Ba 1.2 Cu 3 O 7 - δ superconductor system is higher than that observed for the Gd 1 - 2x Pr x Ca x Sr 0.8 Ba 1.2 Cu 3 O 7 - δ system. For the Gd 0.8 Pr 0.1 Ca 0.1 Sr 0.8 Ba 1.2 Cu 3 O 7 - δ sample, after heating in argon followed by oxygen annealing, the orthorhombicity increases accompanied by 10 K increase in Tc. These results show that though our data indicate an ion-size effect, the Tc suppression rate dTc/dx depends very much on the heat treatment adopted to prepare the samples.

Structural and superconducting properties of Y1-2xPrxCaxBa2Cu3O7-?: high-Tc superconductors

2004 ◽  
Vol 201 (9) ◽  
pp. 2082-2088 ◽  
Author(s):  
N. Charoenthai ◽  
P. Winotai ◽  
R. Suryanarayanan
Keyword(s):  
Superconducting Properties ◽  
High Tc Superconductors ◽  
High Tc

scholarly journals Erratum to: “Magnetic and Superconducting Properties of FeAs-Based High-Tc Superconductors with Gd,”

JETP Letters ◽  
2010 ◽  
Vol 90 (10) ◽  
pp. 690-690
Author(s):  
E. P. Khlybov ◽  
O. E. Omelyanovsky ◽  
A. Zaleski ◽  
A. V. Sadakov ◽  
D. R. Gizatulin ◽  
...  
Keyword(s):  
Superconducting Properties ◽  
High Tc Superconductors ◽  
High Tc

Superconducting Properties of Substituted Oxides Bi2Sr2−xLaxCuO6+y and Bi2Sr2Ca1−xYxCu2O8+y Neutron Diffraction of Bi2Sr1.6La0.4CuO6+y and Bi2CaLaCuO6+y

1989 ◽  
Vol 156 ◽  
Author(s):  
J. Darriet ◽  
J. A. Alonso ◽  
P. Burlet ◽  
B. Chevalier ◽  
B. Lepine ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
Critical Temperature ◽  
Neutron Diffraction ◽  
Positive Charge ◽  
Superconducting Transition ◽  
Superconducting Properties ◽  
High Tc Superconductors ◽  
High Tc ◽  
Zero Resistance

ABSTRACTThe substituted oxides Bi2Sr2−xLaxCuO6+y and Bi2Sr2Ca1−xYxCu2O8+y isostructural to the n = 1 and n = 2 members of the high Tc superconductors have been prepared. The solid solution Bi2Sr2−xLaxCuO6+y shows a superconducting transition for 0.2–0.25<x<0.5 with an onset Tc near 30K and zero resistance temperatures which depend on x and the heat treatment. For x = 1 the isostructural phases Bi2ALaCuO6.5+y with A = Ca or Ba have also been synthesized and are not superconducting. A modelfor the localization of the oxygen atoms is proposed based on neutron diffraction of Bi2Sr1.6La0.4CuO6+y and Bi2CaLaCuO6+y.The Bi2Sr2Ca1−xYxCu2O8+y solid solution exhibits a superconducting transition for 0<x <0.7. The critical temperature remains almost constant (85–90K) for 0<x <0.3 and then decreases rapidly. The oxygen content value 8.65 for Bi2Sr2YCu2O8+y agrees well with the increase of the positive charge when calcium is replaced by yttrium.

Effect of Oxygen Annealing on Low-Resistivity Contactsfor High-Tc Superconductors

1987 ◽  
Vol 99 ◽  
Author(s):  
J. W. Ekin ◽  
A. J. Panson ◽  
B. A. Blankenship
Keyword(s):  
Superconducting Transition ◽  
High Tc Superconductors ◽  
High Tc ◽  
Low Resistivity ◽  
Strongly Nonlinear ◽  
Current Characteristics ◽  
Effect Of Oxygen ◽  
Thermosonic Wire Bonding ◽  
External Connections ◽  
Contact Resistivities

ABSTRACTA method for making low resistivity contacts to high-Tc superconductors has been developed, consisting of depositing noble metal contact pads (silver or gold) on a clean superconductor surface at low temperatures (<150°C). After annealing the silver contact pads in oxygen at intermediate temperatures (<500°C) for one hour, contact resistivities less than 2 × 10'° Ω-cm2 at 76 K are obtained, about six orders of magnitude less than for indium-solder contacts. Before annealing, the contact resistivities are still very low, in the 10-6 to 10-5 Ω-cm range at 76 K, which would be useful when contacts with low fabrication temperatures are required. The voltage-current characteristics of the contacts are strongly nonlinear after annealing, having a superconducting transition character. This is ascribed to the critical current of the superconducting material being exceeded at the contact interface. External connections to the contact pads have been made using both solder and thermosonic wire-bonding techniques.

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