Possibility of High-Tc Copper Fluoride Oxide Superconductors

1987 ◽  
Vol 99 ◽  
Author(s):  
P. T. Wu ◽  
R. S. Liu ◽  
H. M. Sung ◽  
J. H. Rung
Keyword(s):  
Solid State ◽  
Room Temperature ◽  
Complete Loss ◽  
Oxide Superconductors ◽  
High Tc ◽  
Gel Method ◽  
Loss Of Resistance ◽  
Zero Resistance ◽  
Room Temperature Superconductivity

ABSTRACTSuperconductivity of YBa2Cu3FxOy system prepared by using a mixed solid state and gel method. A consistent and non-zero resistance drop near 280K was achieved in the nominal YBa2Cu3FxOy system for x=l and 2, with complete loss of resistance at 90K. The metal-semiconductor transition occurs at x value between 2 and 3. Temporal room temperature superconductivity with zero resistance was observed in a YBa2Cu3F2Oy sample at 308K. The phenomenon lasted for three minutes and was not reproducible.

scholarly journals Fermi-Bose Mixtures and BCS-BEC Crossover in High-Tc Superconductors

2019 ◽  
Vol 4 (2) ◽  
pp. 51 ◽  
Author(s):  
Maxim Yu. Kagan ◽  
Antonio Bianconi
Keyword(s):  
Room Temperature ◽  
High Tc Superconductors ◽  
High Tc ◽  
Magnetic Traps ◽  
Unconventional Superconductors ◽  
Topological Superconductors ◽  
Coupling Approach ◽  
Bose Einstein ◽  
Room Temperature Superconductivity ◽  
Twisted Graphene

In this review article we consider theoretically and give experimental support to the models of the Fermi-Bose mixtures and the BCS-BEC (Bardeen Cooper Schrieffer–Bose Einstein) crossover compared with the strong-coupling approach, which can serve as the cornerstones on the way from high-temperature to room-temperature superconductivity in pressurized metallic hydrides. We discuss some key theoretical ideas and mechanisms proposed for unconventional superconductors (cuprates, pnictides, chalcogenides, bismuthates, diborides, heavy-fermions, organics, bilayer graphene, twisted graphene, oxide hetero-structures), superfluids and balanced or imbalanced ultracold Fermi gases in magnetic traps. We build a bridge between unconventional superconductors and recently discovered pressurized hydrides superconductors H3S and LaH10 with the critical temperature close to room temperature. We discuss systems with a line of nodal Dirac points close to the Fermi surface and superconducting shape resonances, and hyperbolic superconducting networks which are very important for the development of novel topological superconductors, for the energetics, for the applications in nano-electronics and quantum computations.

scholarly journals Towards Room-Temperature Superconductivity

2020 ◽  
Author(s):  
Jacob Szeftel ◽  
Nicolas Sandeau ◽  
Michel Abou Ghantous ◽  
Muhammad El Saba
Keyword(s):  
Critical Temperature ◽  
Band Structure ◽  
Electron Concentration ◽  
Stability Criterion ◽  
Room Temperature ◽  
High Tc ◽  
Electron Band ◽  
Room Temperature Superconductivity ◽  
Critical Temperature Tc ◽  
Electron Band Structure

By taking advantage of a stability criterion established recently, the critical temperature Tc is reckoned with help of the microscopic parameters, characterising the normal and superconducting electrons, namely the independent-electron band structure and a repulsive two-electron force. The emphasis is laid on the sharp Tc dependence upon electron concentration and inter-electron coupling, which might offer a practical route toward higher Tc values and help to understand why high-Tc compounds exhibit such remarkable properties.

Preparation of Bi-Pb-Sr-Ca-Cu-O Superconductor By Thermal Decomposition of an Edta Colloid

1990 ◽  
Vol 180 ◽  
Author(s):  
H.S. Koo ◽  
C.K. Chiang ◽  
Y.T. Huang ◽  
G.C. Tu
Keyword(s):  
Thermal Decomposition ◽  
Solid State ◽  
Solid State Reactions ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
Microstructural Characteristics ◽  
High Tc ◽  
X Ray ◽  
Metal Nitrates ◽  
Zero Resistance

ABSTRACTHigh-Tc superconducting Bi-Pb-Sr-Ca-Cu oxide with zero resistance temperature at above lOOK has been synthesized via the use of ethylenediamine-tetra-acetate(EDTA) colloid and corresponding metal nitrates. Remarkable sinterability of the precursor requires shorter time to achieve superconducting phases than conventional solid-state reactions. Superconducting properties were measured electrically and magnetically. The thermal decomposition, X-ray diffraction and microstructural characteristics of the precursor and the sintered samples were also discussed.

STUDY OF HIGH-Tc SUPERCONDUCTING MATERIALS IN (Bi.Pb)-Sr-Ca-Cu-O SYSTEM

1989 ◽  
Vol 03 (04) ◽  
pp. 595-601 ◽  
Author(s):  
YUGUI WANG ◽  
XINPING JIAO ◽  
JINSONG WANG ◽  
NANLING WANG ◽  
GUCHANG HAN
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Magnetization Measurement ◽  
Superconducting Phase ◽  
Superconducting Materials ◽  
High Tc ◽  
Preliminary Results ◽  
Zero Resistance ◽  
Weak Pinning

The high-T c superconducting materials in (Bi.Pb)-Sr-Ca-Cu-O system with zero resistance temperature of 104 K have been made by solid state reaction. The system has been compared with BiSrCaCu 2 O y composition. The preliminary results show that Pb would make the superconducting polycrystalline grains grow smaller resulting in the separation of 100–110 K and 80 K superconducting crystalline grains and connectivity among the high-T c phase grains. By comparison, the proportion of superconducting phase is not increased in the Pb doped multiphase samples. The magnetization measurement indicates that all of them belong to the weak pinning superconductors.

HIGH Tc SUPERCONDUCTING FILMS AND POWDERS SYNTHESIZED BY SOL-GEL PROCESSES

1989 ◽  
Vol 03 (04) ◽  
pp. 301-306 ◽  
Author(s):  
F. CHEN ◽  
S. LUO ◽  
N. LI ◽  
C. LI ◽  
B. JIE ◽  
...  
Keyword(s):  
Grain Size ◽  
Sol Gel ◽  
Fine Powder ◽  
Superconducting Films ◽  
Organic Amine ◽  
Solid Reaction ◽  
High Tc ◽  
Gel Method ◽  
Average Grain Size ◽  
Zero Resistance

A sol-gel method producing slice-form fine powder of high T c Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O by organic amine-precipitation is presented. The average grain size of such powders is much smaller than that by the conventional solid-reaction. Superconducting films of Y-Ba-Cu-O with zero resistance T co =82.5 K prepared by this method manifest strong (001) texture. The reason of preferential orientation on polycrystal substrate is discussed.

HIGH-Tc SUPERCONDUCTIVITY IN THE Y-Ba-Al-Cu OXIDES SYSTEM

1987 ◽  
Vol 01 (05n06) ◽  
pp. 259-263
Author(s):  
YUHUAN XU ◽  
ZHONGRONG LI ◽  
CHAORUI LI ◽  
BIN LIU ◽  
XIANDUAN LIN ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
High Tc ◽  
High Tc Superconductivity ◽  
Ceramic Samples ◽  
Zero Resistance ◽  
Ceramic Manufacture

The ceramics with the composition of YBa2AlxCu3−xO9−n(0.5≤x≤2) have been synthesized directly from a solid-state reaction of Y2O3, BaCO3, A12O3, and CuO by general ceramic manufacture. The stable high-Tc superconductivity with a resistive mid-point of 101K and zero resistance temperature of 99K has been observed in ceramic samples with the composition of YBa2Al0.5Cu2.5O9−n.

scholarly journals Towards Room-Temperature Superconductivity

2021 ◽  
Author(s):  
Jacob Szeftel ◽  
Nicolas Sandeau ◽  
Michel Abou Ghantous ◽  
Muhammad El Saba
Keyword(s):  
Critical Temperature ◽  
Band Structure ◽  
Electron Concentration ◽  
Stability Criterion ◽  
Room Temperature ◽  
High Tc ◽  
Electron Band ◽  
Room Temperature Superconductivity ◽  
Critical Temperature Tc ◽  
Electron Band Structure

By taking advantage of a stability criterion established recently, the critical temperature Tc is reckoned with help of the microscopic parameters, characterising the normal and superconducting electrons, namely the independent-electron band structure and a repulsive two-electron force. The emphasis is laid on the sharp Tc dependence upon electron concentration and inter-electron coupling, which might offer a practical route toward higher Tc values and help to understand why high-Tc compounds exhibit such remarkable properties.

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