THERMOPOWER ANISOTROPY OF YBa2Cu3O7−δ SINGLE CRYSTALS

1989 ◽  
Vol 03 (03) ◽  
pp. 409-413 ◽  
Author(s):  
SHU-YUAN LIN ◽  
LI LU ◽  
HONG-MIN DUAN ◽  
BEI-HAI MA ◽  
DIAN-LIN ZHANG
Keyword(s):  
Transition Temperature ◽  
Single Crystals ◽  
Superconducting Transition Temperature ◽  
Room Temperature ◽  
Superconducting Transition ◽  
Strong Anisotropy ◽  
Metallic Behavior

The thermopower of YBa 2 Cu 3 O 7−δ single crystals has been measured from 300 K down to superconducting transition temperature. Strong anisotropy was observed. While the thermopower along ab-plane slightly increased with decreasing temperature, reaching 5 ~ 8 μ V/K around 120 K, the thermopower along c-axis showed typical metallic behavior with room temperature value as large as ~ 30 μ V/K .

scholarly journals Computational Intelligence Approach for Estimating Superconducting Transition Temperature of Disordered MgB2Superconductors Using Room Temperature Resistivity

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Taoreed O. Owolabi ◽  
Kabiru O. Akande ◽  
Sunday O. Olatunji
Keyword(s):  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Room Temperature ◽  
Optimization Technique ◽  
Support Vector ◽  
Measuring Instruments ◽  
Room Temperature Resistivity ◽  
Superconducting Transition ◽  
Experimental Values ◽  
Temperature Resistivity

Doping and fabrication conditions bring about disorder in MgB2superconductor and further influence its room temperature resistivity as well as its superconducting transition temperature (TC). Existence of a model that directly estimatesTCof any doped MgB2superconductor from the room temperature resistivity would have immense significance since room temperature resistivity is easily measured using conventional resistivity measuring instrument and the experimental measurement ofTCwastes valuable resources and is confined to low temperature regime. This work develops a model, superconducting transition temperature estimator (STTE), that directly estimatesTCof disordered MgB2superconductors using room temperature resistivity as input to the model. STTE was developed through training and testing support vector regression (SVR) with ten experimental values of room temperature resistivity and their correspondingTCusing the best performance parameters obtained through test-set cross validation optimization technique. The developed STTE was used to estimateTCof different disordered MgB2superconductors and the obtained results show excellent agreement with the reported experimental data. STTE can therefore be incorporated into resistivity measuring instruments for quick and direct estimation ofTCof disordered MgB2superconductors with high degree of accuracy.

scholarly journals Research Progress on Ni-Based Antiperovskite Compounds

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
P. Tong ◽  
Y. P. Sun
Keyword(s):  
Phase Diagram ◽  
Transition Temperature ◽  
Single Crystals ◽  
Superconducting Transition Temperature ◽  
Spin Fluctuations ◽  
Research Progress ◽  
Future Research ◽  
Magnetic Element ◽  
Superconducting Transition ◽  
Cubic Structure

The superconductivity in antiperovskite compound MgCNi3was discovered in 2001 following the discovery of the superconducting MgB2. In spite of its lower superconducting transition temperature (8 K) than MgB2(39 K), MgCNi3has attracted considerable attention due to its high content of magnetic element Ni and the cubic structure analogous to the perovskite cuprates. After years of extensive investigations both theoretically and experimentally, however, it is still not clear whether the mechanism for superconductivity is conventional or not. The central issue is if and how the ferromagnetic spin fluctuations contribute to the cooper paring. Recently, the experimental results on the single crystals firstly reported in 2007 trend to indicate a conventionals-wave mechanism. Meanwhile many compounds neighboring to MgCNi3were synthesized and the physical properties were investigated, which enriches the physics of the Ni-based antiperovskite compounds and help understand the superconductivity in MgCNi3. In this paper, we summarize the research progress in these two aspects. Moreover, a universal phase diagram of these compounds is presented, which suggests a phonon-mediated mechanism for the superconductivity, as well as a clue for searching new superconductors with the antiperovskite structure. Finally, a few possible scopes for future research are proposed.

Superconductivity of La(2-x)BaxCuO4

1987 ◽  
Vol 99 ◽  
Author(s):  
A. R. Moodenbaugh ◽  
Y. Xu ◽  
M. Suenaga
Keyword(s):  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Room Temperature ◽  
Superconducting Transition

Superconductivity near 30 K in the La-Ba-Cu-O system, first observed by Bednorz and Müller [1], was soon found to be attributable to the K2NiF4-type (at room temperature) compound La(2-x)BxxCuO4 [2]. Substitution of Sr and Ca for Ba yielded superconducting systems, also with high superconducting transition temperature Tc. Replacement of La by Y led to the discovery of the 90 K superconductors.

Pressure dependence of the superconducting transition temperature in single crystals ofTl2Ba2Ca2Cu3O10−x

1993 ◽  
Vol 47 (9) ◽  
pp. 5524-5527 ◽  
Author(s):  
D. D. Berkley ◽  
E. F. Skelton ◽  
N. E. Moulton ◽  
M. S. Osofsky ◽  
W. T. Lechter ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Single Crystals ◽  
Pressure Dependence ◽  
Superconducting Transition Temperature ◽  
Superconducting Transition

Cd additive effect on self-flux growth of Cs-intercalated NbS2 superconducting single crystals

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Masanori Nagao ◽  
Akira Miura ◽  
Yuki Maruyama ◽  
Satoshi Watauchi ◽  
Yoshihiko Takano ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Single Crystals ◽  
Superconducting Transition Temperature ◽  
Additive Effect ◽  
Flux Growth ◽  
Superconducting Transition

Abstract Single crystals of Cs-intercalated NbS2 (Cs x NbS2) were synthesized using a CsCl/KCl self-flux. The size and Cs content of Cs x NbS2 single crystals increased upon adding Cd metal into the starting materials. When 10–30 at% of Cd per Nb was provided in the starting materials, plate-like Cs x NbS2 (x ∼ 0.3) single crystals with 1–2 mm in size and 10–100 μm in thickness were obtained. The superconducting transition temperature of these Cs x NbS2 single crystals was 1.65 K.

EFFECT OF PRESSURE ON INTERLAYER COUPLING AND SUPERCONDUCTING TRANSITION TEMPERATURE OF Bi-2201 AND Bi-2212

1999 ◽  
Vol 13 (29n31) ◽  
pp. 3744-3746 ◽  
Author(s):  
AUGUST YURGENS ◽  
DAG WINKLER ◽  
TORD CLAESON ◽  
TAKASHI MURAYAMA ◽  
YOICHI ANDO
Keyword(s):  
Transition Temperature ◽  
Critical Temperature ◽  
Hydrostatic Pressure ◽  
Single Crystals ◽  
Critical Current ◽  
Superconducting Transition Temperature ◽  
Interlayer Coupling ◽  
Superconducting Transition ◽  
Effect Of Pressure

We used the hydrostatic pressure P<1 GPa as a tool to change the c-axis interlayer coupling of Bi 2 Sr 1.5 La 0.5 CuO 6+δ (Bi-2201) and Bi 2 Sr 2 CaCu 2 O 8+δ (Bi-2212) single crystals. The c-axis critical current, as a measure of the interlayer coupling, drastically increases with pressure (up to 270% GPa -1). The superconducting critical temperature, on the contrary, only slightly increases with a rate of ≈ 2 - 6% GPa -1, This implies that the CuO-interlayer coupling has little effect on Tc in Bi-2201.

Phonon Anomaly at Tc In (Y/Er)Ba2Cu3O7–δ

1989 ◽  
Vol 169 ◽  
Author(s):  
Rajeshwar P. Sharma ◽  
L. E. Rehn ◽  
P. Baldo ◽  
J. Z. Liu
Keyword(s):  
Transition Temperature ◽  
Single Crystals ◽  
Superconducting Transition Temperature ◽  
Structural Changes ◽  
Abrupt Change ◽  
Superconducting Transition ◽  
Ion Channeling ◽  
Atomic Displacements ◽  
Induced Changes ◽  
Phonon Anomaly

AbstractIon channeling in single crystals of (Y/Er)Ba2Cu3O7–δ reveal an abrupt change (~0.01Å) at the superconducting transition temperature (Tc) in displacements of the Cu and O atoms perpendicular to the [001] direction. This anomalous change in atomic displacements shifts directly with stoichiometry-induced changes in Tc. Blocking patterns indicate no large structural changes across Tc.

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