Evolution of atomic ordering in fine-grained YBa2Cu3O y high-temperature superconductors and its effect on superconducting transition temperature

2013 ◽  
Vol 77 (3) ◽  
pp. 242-245 ◽  
Author(s):  
L. G. Mamsurova ◽  
K. S. Pigalskiy ◽  
A. A. Vishnev
Keyword(s):  
High Temperature ◽  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
High Temperature Superconductors ◽  
Superconducting Transition ◽  
Atomic Ordering ◽  
Fine Grained

scholarly journals Enhancing Superconductivity of the Nonmagnetic Quasiskutterudites by Atomic Disorder

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5830
Author(s):  
Andrzej Ślebarski ◽  
Maciej M. Maśka
Keyword(s):  
High Temperature ◽  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
High Temperature Superconductors ◽  
Superconducting Phase ◽  
Length Scale ◽  
Superconducting Transition ◽  
Atomic Disorder ◽  
Strong Inhomogeneity ◽  
Related Compounds

We investigated the effect of enhancement of superconducting transition temperature Tc by nonmagnetic atom disorder in the series of filled skutterudite-related compounds (La3M4Sn13, Ca3Rh4Sn13, Y5Rh6Sn18, Lu5Rh6Sn18; M= Co, Ru, Rh), where the atomic disorder is generated by various defects or doping. We have shown that the disorder on the coherence length scale ξ in these nonmagnetic quasiskutterudite superconductors additionally generates a non-homogeneous, high-temperature superconducting phase with Tc⋆>Tc (dilute disorder scenario), while the strong fluctuations of stoichiometry due to increasing doping can rapidly increase the superconducting transition temperature of the sample even to the value of Tc⋆∼2Tc (dense disorder leading to strong inhomogeneity). This phenomenon seems to be characteristic of high-temperature superconductors and superconducting heavy fermions, and recently have received renewed attention. We experimentally documented the stronger lattice stiffening of the inhomogeneous superconducting phase Tc⋆ in respect to the bulk Tc one and proposed a model that explains the Tc⋆>Tc behavior in the series of nonmagnetic skutterudite-related compounds.

scholarly journals Superconductor-to-metal transition in overdoped cuprates

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Zi-Xiang Li ◽  
Steven A. Kivelson ◽  
Dung-Hai Lee
Keyword(s):  
High Temperature ◽  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
High Temperature Superconductors ◽  
Theoretical Framework ◽  
Superconducting Transition ◽  
Wave Pairing ◽  
Superconducting Correlations

AbstractWe present a theoretical framework for understanding the behavior of the normal and superconducting states of overdoped cuprate high temperature superconductors in the vicinity of the doping-tuned quantum superconductor-to-metal transition. The key ingredients on which we focus are d-wave pairing, a flat antinodal dispersion, and disorder. Even for homogeneous disorder, these lead to effectively granular superconducting correlations and a superconducting transition temperature determined in large part by the superfluid stiffness rather than the pairing scale.

ELECTRON-PHONON INTERACTION FOR AN ANALYTIC SOLUTION TO THE BCS EQUATION FOR THE HIGH TEMPERATURE SUPERCONDUCTORS

1991 ◽  
Vol 05 (20) ◽  
pp. 1349-1353 ◽  
Author(s):  
H. C. GUPTA
Keyword(s):  
High Temperature ◽  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Analytic Solution ◽  
Energy Gap ◽  
High Temperature Superconductors ◽  
Superconducting Transition ◽  
Phonon Interaction ◽  
Electron Phonon Interaction ◽  
Gap Parameter

An energy dependent electron-phonon interaction has been used in the BCS equation. This provides an exactly solvable analytic solution to the BCS equation for the superconducting transition temperature and the gap parameter at absolute zero. These analytically obtained equations reduce to standard BCS form when temperature is small. These equations are applicable to low as well as high temperature superconductors successfully for their superconducting transition temperature and the energy gap parameter.

ELECTRICAL AND MAGNETIC MEASUREMENTS IN K DOPED GdBa2Cu3O7−d HIGH TEMPERATURE SUPERCONDUCTORS

1993 ◽  
Vol 07 (18) ◽  
pp. 3273-3279 ◽  
Author(s):  
V. VIDYALAL ◽  
K. RAJASREE ◽  
C.P.G. VALLABHAN ◽  
PREETHI CICILY THOMAS ◽  
V. UNNIKRISHNAN NAYAR
Keyword(s):  
High Temperature ◽  
Transition Temperature ◽  
Ceramic Material ◽  
Superconducting Transition Temperature ◽  
Sintering Temperature ◽  
Magnetic Measurements ◽  
High Temperature Superconductors ◽  
Superconducting Transition

Stable and reproducible superconducting transition between 92 K and 100 K has been observed both resistively and magnetically in potassium doped GdBa 2 Cu 3 O 7−δ ceramic material. It has been found that the sintering temperature as well as stoichiometry plays an important role in determining the value of T c . Subtle changes in T c occur for certain weight % of K. The effect of changing composition on the superconducting transition temperature is also reported here.

scholarly journals Higher superconducting transition temperature by breaking the universal pressure relation

2019 ◽  
Vol 116 (6) ◽  
pp. 2004-2008 ◽  
Author(s):  
Liangzi Deng ◽  
Yongping Zheng ◽  
Zheng Wu ◽  
Shuyuan Huyan ◽  
Hung-Cheng Wu ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
High Temperature ◽  
Transition Temperature ◽  
Density Functional ◽  
High Temperature Superconductors ◽  
Density Functional Theory Calculations ◽  
Universal Relation ◽  
Superconducting Transition ◽  
Functional Theory ◽  
A Charge

By investigating the bulk superconducting state via dc magnetization measurements, we have discovered a common resurgence of the superconducting transition temperatures (Tcs) of the monolayer Bi2Sr2CuO6+δ(Bi2201) and bilayer Bi2Sr2CaCu2O8+δ(Bi2212) to beyond the maximum Tcs (Tc-maxs) predicted by the universal relation between Tcand doping (p) or pressure (P) at higher pressures. The Tcof underdoped Bi2201 initially increases from 9.6 K at ambient to a peak at 23 K at 26 GPa and then drops as expected from the universal Tc-P relation. However, at pressures above 40 GPa, Tcrises rapidly without any sign of saturation up to 30 K at 51 GPa. Similarly, the Tcfor the slightly overdoped Bi2212 increases after passing a broad valley between 20 and 36 GPa and reaches 90 K without any sign of saturation at 56 GPa. We have, therefore, attributed this Tcresurgence to a possible pressure-induced electronic transition in the cuprate compounds due to a charge transfer between the Cu 3dx2−y2and the O 2pbands projected from a hybrid bonding state, leading to an increase of the density of states at the Fermi level, in agreement with our density functional theory calculations. Similar Tc-P behavior has also been reported in the trilayer Br2Sr2Ca2Cu3O10+δ(Bi2223). These observations suggest that higher Tcs than those previously reported for the layered cuprate high-temperature superconductors can be achieved by breaking away from the universal Tc-P relation through the application of higher pressures.

Volume dependence of the superconducting transition temperature for the high-temperature superconductorHgBa2Ca2−xPbxCu3O8+δ

1994 ◽  
Vol 50 (18) ◽  
pp. 13778-13785 ◽  
Author(s):  
Charles C. Kim ◽  
A. R. Drews ◽  
E. F. Skelton ◽  
S. B. Qadri ◽  
M. S. Osofsky ◽  
...  
Keyword(s):  
High Temperature ◽  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Superconducting Transition ◽  
Volume Dependence

THERMAL CONDUCTIVITY OF HIGH TEMPERATURE SUPERCONDUCTORS

1991 ◽  
Vol 05 (12) ◽  
pp. 2003-2035 ◽  
Author(s):  
MANUEL D. NUÑEZ REGUEIRO ◽  
DARÍO CASTELLO
Keyword(s):  
Thermal Conductivity ◽  
High Temperature ◽  
Transition Temperature ◽  
Phonon Scattering ◽  
High Temperature Superconductors ◽  
Low Energy ◽  
Disordered Materials ◽  
Superconducting Transition ◽  
Universal Pattern ◽  
Heat Carriers

We review and analyze the data on the thermal conductivity of both ceramic and single crystal samples of high temperature superconductors. A universal pattern can be extracted and interpreted in the following way: phonons are the main heat carriers in these materials, and in the high temperature range the thermal conductivity κ is almost constant due to phonon scattering against disorder; below the superconducting transition temperature κ increases as phonon scattering against carriers condensing into the superconducting state decreases and at still lower temperatures there is a region in which a T2 law is obeyed that most probably is due to resonant phonon scattering against low energy excitations, i.e. tunneling systems similar to those found in disordered materials. The origin of the relevant disorder is discussed.

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.

Ultra-Low-Field Squid Magnetic Measurements on High Temperature Ceramic YBaCuO Superconductors

1987 ◽  
Vol 99 ◽  
Author(s):  
D. C. Cronemeyer ◽  
A. P. Malozemoff ◽  
T. R. Mcguire
Keyword(s):  
High Temperature ◽  
Transition Temperature ◽  
Ceramic Sample ◽  
Superconducting Transition Temperature ◽  
Magnetic Measurements ◽  
Zero Field ◽  
Superconducting Transition ◽  
Temperature Range ◽  
Low Field ◽  
The Difference

ABSTRACTWe report ultra-low-field (5 mOe - 1 Oe) magnetic measurements on a ceramic sample of YBaCuO. A positive remanent moment is observed which accurately equals the difference of the field-cooled and zero-field-cooled moments throughout the temperature range. At higher fields this relationship breaks down. A reversible region is observed near the superconducting transition temperature which is independent of field. These results are discussed in the context of recent models.

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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