Effects of isovalent substitutions and heat treatment on structural and superconducting properties of high-critical temperature superconductors

2020 ◽  
Vol 22 ◽  
pp. 140-145
Author(s):  
Keltoum Khallouq ◽  
Abdelhakim Nafidi ◽  
Abdeljabar Aboulkassim ◽  
Essediq Youssef El Yakoubi ◽  
Es-saïd Es-Salhi
Keyword(s):  
Heat Treatment ◽  
Critical Temperature ◽  
High Critical Temperature ◽  
Superconducting Properties

Connectivity and flux pinning improvements in Ag-clad BSCCO-2223 tapes produced by changes in the cooling rate

1997 ◽  
Vol 12 (11) ◽  
pp. 2997-3008 ◽  
Author(s):  
J. A. Parrell ◽  
D. C. Larbalestier ◽  
G. N. Riley ◽  
Q. Li ◽  
W. L. Carter ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Critical Temperature ◽  
Cooling Rate ◽  
Flux Pinning ◽  
Irreversibility Field ◽  
Superconducting Properties ◽  
Temperature Transition ◽  
Slow Cooling ◽  
Reaction Heat ◽  
Final Reaction

The rate at which Ag-clad (Bi, Pb)2Sr2Ca2Cu3Ox tapes are cooled from their final reaction heat treatment influences both the intergranular connectivity and intragranular flux pinning strength of the polycrystalline filaments. As the cooling rate from 825 °C to 730 °C in 7.5% O2 was decreased over a range of 5 °C/min to 0.005 °C/min, Jc (77 K, 0 T) increased from ∼8 to ∼24 kA/cm2, and the irreversibility field increased from, ∼120 to, ∼200 mT. The Jc (4.2 K, 0 T) increased in a similar fashion. Cooling slowly also sharpened the critical temperature transition and increased the critical onset temperature from 107 K to 109 K. These improvements in the superconducting properties occurred despite partial decomposition of the (Bi, Pb)2Sr2Ca2Cu3Ox phase into non-superconducting impurity phases during the slow cooling. A microstructural basis for these multiple effects is described.

A Hydroxycarbonate Route to Superconductor Precursor Powders

1987 ◽  
Vol 99 ◽  
Author(s):  
J. A. Voigt ◽  
B. C. Bunker ◽  
D. H. Doughty ◽  
D. L. Lamppa ◽  
K. M. Kimball
Keyword(s):  
Critical Temperature ◽  
Structural Integrity ◽  
Nitrate Solution ◽  
High Density ◽  
Tetramethylammonium Hydroxide ◽  
Precipitation Process ◽  
High Critical Temperature ◽  
Superconducting Properties ◽  
Superconducting Ceramics ◽  
Precursor Powders

ABSTRACTA precipitation process is described for the preparation of powders that can be thermally decomposed to form high critical temperature superconductors such as YBa2Cu3O7. In the process, a cationic solution (a concentrated chloride or nitrate solution) is instantaneously mixed with an anionie solution (a mixture of tetramethylammonium hydroxide and carbonate) to produce a metal-hydroxycarbonate precipitate having the metal stoichiometry of the desired superconducting oxide. The calcining and sintering of the precipitates is critical in controlling the structural integrity and morphology of the superconducting ceramics made from the chem-prep powders, as well as controlling superconducting properties. Under appropriate conditions, high density (>95%) materials that exhibit good superconducting characteristics can be prepared with the chem-prep powders.

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.

Two dimensional CrGa2Se4: A spin-gapless ferromagnetic semiconductor with inclined uniaxial anisotropy

Nanoscale ◽  
2021 ◽  
Author(s):  
Qian Chen ◽  
Ruqian Wang ◽  
Zhaocong Huang ◽  
Shijun Yuan ◽  
Haowei Wang ◽  
...  
Keyword(s):  
Critical Temperature ◽  
Material Science ◽  
2D Materials ◽  
Uniaxial Anisotropy ◽  
Magnetic Semiconductor ◽  
Ferromagnetic Semiconductor ◽  
Two Dimensional ◽  
High Critical Temperature

The magnetic semiconductor with high critical temperature has long been the focus in material science and recently is also known as one of the fundamental questions in two-dimensional (2D) materials....

A Self-Doped Oxygen-Free High-Critical-Temperature (High-Tc) Superconductor: SmFFeAs

2019 ◽  
Vol 58 (22) ◽  
pp. 15401-15409 ◽  
Author(s):  
Dan Lin ◽  
Han-Shu Xu ◽  
Jingjing Luo ◽  
Haoliang Huang ◽  
Yalin Lu ◽  
...  
Keyword(s):  
Critical Temperature ◽  
High Critical Temperature ◽  
High Tc ◽  
High Tc Superconductor

Characterisation of high-critical temperature superconducting materials by ICP-AES technique

1992 ◽  
Vol 342 (4-5) ◽  
pp. 367-369 ◽  
Author(s):  
Madhuri J. Kulkarni ◽  
Aparna A. Argekar ◽  
S. K. Thulasidas ◽  
A. G. Page ◽  
M. D. Sastry
Keyword(s):  
Critical Temperature ◽  
Superconducting Materials ◽  
High Critical Temperature
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