scholarly journals Linear electron-hole-electron pair model of high-temperature superconductivity in La sub 2-x M sub x CuO sub 4 and YBa sub 2 Cu sub 3 O sub 7-y : 2, Dependence of the superconducting transition temperatures on pressure and on hole concentration

1989 ◽  
Author(s):  
Myung-Hwan Whangbo ◽  
M. Evain ◽  
E. Canadell ◽  
J.M. Williams
Keyword(s):  
High Temperature ◽  
Electron Pair ◽  
High Temperature Superconductivity ◽  
Hole Concentration ◽  
Transition Temperatures ◽  
Superconducting Transition ◽  
Linear Electron ◽  
Electron Hole ◽  
Pair Model

HIGH TEMPERATURE SUPERCONDUCTIVITY IN Y-Ba-Cu-Nb-O SYSTEM

1988 ◽  
Vol 02 (03n04) ◽  
pp. 435-441 ◽  
Author(s):  
N. G. SURESHA ◽  
S. HIGO ◽  
Y. HAKURAKU ◽  
T. OTAWA ◽  
Y. HONJO ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
High Temperature ◽  
Powder Diffraction ◽  
High Temperature Superconductivity ◽  
Gradual Change ◽  
Transition Temperatures ◽  
Superconducting Transition ◽  
Oxide Superconductor ◽  
X Ray ◽  
Diffraction Patterns

Results of the resistivity and magnetic susceptibility measurements for an oxide superconductor with nominal compositions of Y 1 Ba 2( Cu 1−x Nb x)3 O 6+δ and Y 0.4 Ba 0.6 ( Cu 1−x Nb x) O 2+δ where x = 0.1, 0.15, 0.2, are reported. Superconducting transition temperatures, T c onset (T co ) and T c final (T cf ) are above 90 K and 80 K respectively. We have observed a gradual change in the X-ray powder diffraction patterns of the samples with the change in x.

Crystal Growth of High Temperature Superconductors

MRS Bulletin ◽  
1988 ◽  
Vol 13 (10) ◽  
pp. 56-61 ◽  
Author(s):  
H.J. Scheel ◽  
F. Licci
Keyword(s):  
High Temperature ◽  
Critical Current Density ◽  
Single Crystals ◽  
Critical Current ◽  
Current Density ◽  
Large Scale ◽  
High Temperature Superconductivity ◽  
High Temperature Superconductors ◽  
Superconducting Transition ◽  
Theoretical Understanding

The discovery of high temperature superconductivity (HTSC) in oxide compounds has confronted materials scientists with many challenging problems. These include the preparation of ceramic samples with critical current density of about 106 A/cm2 at 77 K and sufficient mechanical strength for large-scale electrotechnical and magnetic applications and the preparation of epitaxial thin films of high structural perfection for electronic devices.The main interest in the growth of single crystals is for the study of physical phenomena, which will help achieve a theoretical understanding of HTSC. Theorists still do not agree on the fundamental mechanisms of HTSC, and there is a need for good data on relatively defect-free materials in order to test the many models. In addition, the study of the role of defects like twins, grain boundaries, and dislocations in single crystals is important for understanding such parameters as the critical current density. The study of HTSC with single crystals is also expected to be helpful for finding optimum materials for the various applications and hopefully achieving higher values of the superconducting transition temperature Tc than the current maximum of about 125 K. It seems unlikely at present that single crystals will be used in commercial devices, but this possibility cannot be ruled out as crystal size and quality improve.

scholarly journals Fe-based superconducting transition temperature modeling by machine learning: A computer science method

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0255823
Author(s):  
Zhiyuan Hu
Keyword(s):  
Machine Learning ◽  
High Temperature ◽  
Transition Temperature ◽  
High Temperature Superconductors ◽  
Strong Relationship ◽  
Lattice Parameters ◽  
Transition Temperatures ◽  
Superconducting Transition ◽  
Temperature Modeling ◽  
High Transition

Searching for new high temperature superconductors has long been a key research issue. Fe-based superconductors attract researchers’ attention due to their high transition temperature, strong irreversibility field, and excellent crystallographic symmetry. By using doping methods and dopant levels, different types of new Fe-based superconductors are synthesized. The transition temperature is a key indicator to measure whether new superconductors are high temperature superconductors. However, the condition for measuring transition temperature are strict, and the measurement process is dangerous. There is a strong relationship between the lattice parameters and the transition temperature of Fe-based superconductors. To avoid the difficulties in measuring transition temperature, in this paper, we adopt a machine learning method to build a model based on the lattice parameters to predict the transition temperature of Fe-based superconductors. The model results are in accordance with available transition temperatures, showing 91.181% accuracy. Therefore, we can use the proposed model to predict unknown transition temperatures of Fe-based superconductors.

scholarly journals Pressure-induced high-temperature superconductivity retained without pressure in FeSe single crystals

2021 ◽  
Vol 118 (28) ◽  
pp. e2108938118
Author(s):  
Liangzi Deng ◽  
Trevor Bontke ◽  
Rabin Dahal ◽  
Yu Xie ◽  
Bin Gao ◽  
...  
Keyword(s):  
High Temperature ◽  
High Temperature Superconductivity ◽  
Ambient Pressure ◽  
Superconducting Transition ◽  
Elastic Band ◽  
New Era ◽  
Ab Initio Simulations ◽  
Sustained Effort ◽  
Minimal Effort ◽  
Room Temperature Superconductivity

To raise the superconducting-transition temperature (Tc) has been the driving force for the long-sustained effort in superconductivity research. Recent progress in hydrides with Tcs up to 287 K under pressure of 267 GPa has heralded a new era of room temperature superconductivity (RTS) with immense technological promise. Indeed, RTS will lift the temperature barrier for the ubiquitous application of superconductivity. Unfortunately, formidable pressure is required to attain such high Tcs. The most effective relief to this impasse is to remove the pressure needed while retaining the pressure-induced Tc without pressure. Here, we show such a possibility in the pure and doped high-temperature superconductor (HTS) FeSe by retaining, at ambient pressure via pressure quenching (PQ), its Tc up to 37 K (quadrupling that of a pristine FeSe at ambient) and other pressure-induced phases. We have also observed that some phases remain stable without pressure at up to 300 K and for at least 7 d. The observations are in qualitative agreement with our ab initio simulations using the solid-state nudged elastic band (SSNEB) method. We strongly believe that the PQ technique developed here can be adapted to the RTS hydrides and other materials of value with minimal effort.

High-temperature superconductivity in transition metallic hydrides MH11 (M = Mo, W, Nb, and Ta) under high pressure

2021 ◽  
Vol 23 (11) ◽  
pp. 6717-6724
Author(s):  
Mingyang Du ◽  
Zihan Zhang ◽  
Hao Song ◽  
Hongyu Yu ◽  
Tian Cui ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Transition Temperature ◽  
Critical Temperature ◽  
Superconducting Transition Temperature ◽  
High Temperature Superconductivity ◽  
Superconducting Transition ◽  
Optical Phonons ◽  
Acoustic Phonons ◽  
Acoustic Modes

The contribution of optical and acoustic modes to the superconducting transition temperature. The calculated EPC parameter λ, critical temperature (Tc), critical temperature caused by the interaction of electrons with optical phonons (T0c) and acoustic phonons (Tacc).

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