Role of Silver in Yba2Cu3AgXO7-δ Composite Superconductors

1989 ◽  
Vol 169 ◽  
Author(s):  
L. Ganapathi ◽  
Ashok Kumar ◽  
J. Narayan
Keyword(s):  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Alloy Formation ◽  
Peritectic Transformation ◽  
Superconducting Transition ◽  
Superconducting Properties ◽  
Low Concentrations ◽  
Composite Superconductors ◽  
Silver Metal

AbstractSuperconducting properties and microstructures of the YBa2Cu3AgxO7‐δ composites have been studied as a function of silver content, 0 ≤ x ≤ 6, using a variety of techniques.The superconducting transition temperature,Tc, of these composites was found to be the same, ∼ 90 K, for the above range of compositions. The composites with x > 3 are found to have resistivity behavior identical to silver metal above the superconducting transition temperature. The peritectic transformation temperature of the 123 material in the composite is lowered. Alloy formation between Ag and Cu is proposed to take place triggering the peritectic transformation at lower temperatures. The silver is observed in the form of precipitates at very low concentrations of silver, indicating that silver does not substitute for copper in YBa2Cu3AgxO7. Lattice parameters of the composites were found to be invariant throughout the above composition range. The addition of Ag2O in the starting composition seems to stabilize the stoichiometric YBa2Cu3AgxO7 by way of decomposition to Ag and O, also, the better diffusion of oxygen through silver in comparison with that through the superconductor helps the regeneration of superconductivity in the composite superconductor. As a result, the incorporation of oxygen and recovery of superconducting properties is enhanced in the silver composites.For values of x > 3 small quantities of 211 phase were detected along the grain boundaries, which makes the residual composition poor in copper resulting in the formation of non‐superconducting 211 phase.

Superconductivity of embedded lead nano particles in metallic and amorphous matrices

2001 ◽  
Vol 703 ◽  
Author(s):  
K. Chattopadhyay ◽  
V. Bhattacharya ◽  
A. P. Tsai
Keyword(s):  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Magnetic Measurements ◽  
Microstructural Characterization ◽  
Rapid Solidification Processing ◽  
Nano Particles ◽  
Superconducting Transition ◽  
Solidification Processing ◽  
Embedded Particles

ABSTRACTNanodispersed lead in metallic and amorphous matrices was synthesized by rapid solidification processing. The optimum microstructure was tailored to avoid percolation of the particles. With these embedded particles it is possible to study quantitatively the effect of size on the superconducting transition temperature by carrying out quantitative microstructural characterization and magnetic measurements. Our results suggest the role of the matrices in enhancement or depression of superconducting transition temperature of lead. The origin of this difference in behavior with respect to different matrices and sizes is discussed.

scholarly journals Distinct superconducting properties and hydrostatic pressure effects in 2D α- and β-Mo2C crystal sheets

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Yunjie Fan ◽  
Chuan Xu ◽  
Xiang Liu ◽  
Chao Ma ◽  
Yuewei Yin ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Hydrostatic Pressure ◽  
Electronic Properties ◽  
Superconducting Transition Temperature ◽  
Important Influence ◽  
Pressure Effects ◽  
Superconducting Transition ◽  
Superconducting Properties ◽  
Disordered Carbon

Abstract Recently, 2D Mo2C, a new member of the MXene family, has attracted much attention due to the exotic superconducting properties discovered in 2D α-Mo2C. Here, not only 2D α-Mo2C but also 2D β-Mo2C crystal sheets with distinct disordered carbon distributions were successfully grown. 2D β-Mo2C shows a much stronger superconductivity than 2D α-Mo2C, and their superconductivities have different hydrostatic pressure responses. The superconducting transition temperature Tc of 2D α-Mo2C shows a dome-shaped profile under pressure, implying the existence of two competing effects arising from phononic and electronic properties, while for 2D β-Mo2C, Tc decreases monotonically with increasing pressure, possibly due to phonon stiffening. These results indicate that the electronic properties have a more important influence on the superconductivity in 2D α-Mo2C compared to 2D β-Mo2C. The ordered and disordered carbon distributions in 2D α-Mo2C and β-Mo2C, respectively, may be the underlying origin for their different electronic and superconducting properties.

High Pressure Properties of Superconducting Material Palladium

2013 ◽  
Vol 813 ◽  
pp. 327-331
Author(s):  
Wei Min Peng ◽  
Zhong Li Liu ◽  
Hong Zhi Fu
Keyword(s):  
High Pressure ◽  
Perturbation Theory ◽  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Density Functional ◽  
High Pressures ◽  
Ambient Pressure ◽  
Superconducting Transition ◽  
Superconducting Properties ◽  
Density Functional Perturbation Theory

The electronic and the superconducting properties of Pd were studied in the framework of density functional perturbation theory. We explored the superconducting transition temperature for bulk Pd and predicted possible superconductivity at ambient and high pressures. It is found that of Pd is 0.0356 K at ambient pressure and it decreases with pressure.

scholarly journals Single Crystal Growth and Superconducting Properties of Antimony Substituted NdO0.7F0.3BiS2

2017 ◽  
Author(s):  
Satoshi Demura ◽  
Satoshi Otsuki ◽  
Yuita Fujisawa ◽  
Hideaki Sakata
Keyword(s):  
Crystal Growth ◽  
Transition Temperature ◽  
Single Crystal ◽  
Superconducting Transition Temperature ◽  
Single Crystal Growth ◽  
Layered Superconductor ◽  
Superconducting Transition ◽  
Large Decrease ◽  
Superconducting Properties ◽  
Chemical Pressure

Antimony (Sb) Substitution less than 10 % is examined on a single crystal of a layered superconductor NdO0.7F0.3BiS2. Superconducting transition temperature of the substituted samples decreases with increasing Sb concentration. A lattice constant along the c axis showed a large decrease compared with that along the a axis. Since in-plane chemical pressure monotonically decreases with increasing Sb concentration, the suppression of the superconductivity is well described in terms of the decrease in in-plane chemical pressure.

scholarly journals Superconducting properties of very high quality NbN thin films grown by pulsed laser deposition

2019 ◽  
Vol 70 (7) ◽  
pp. 89-94
Author(s):  
Serhii Volkov ◽  
Maros Gregor ◽  
Tomas Roch ◽  
Leonid Satrapinskyy ◽  
Branislav Grančič ◽  
...  
Keyword(s):  
Thin Films ◽  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Pulsed Laser ◽  
Domain Size ◽  
Superconducting Transition ◽  
Superconducting Properties ◽  
Si Substrate ◽  
Coherent Domain Size ◽  
Coherent Domain

Abstract In this work, we study the effect of the various substrates on the growth and superconducting properties of NbN thin films grown by using pulsed laser ablation in a N2 + 1%H2 atmosphere on MgO, Al2O3 and Si substrates. Structural and superconducting analyses of the films demonstrate that using MgO and Al2O3 substrates can significantly improve the film properties compared to Si substrate. The X-ray diffraction data indicate that MgO and Al2O3 substrates produce highly oriented superconducting NbN films with large coherent domain size in the out-of plane direction on the order of layer thickness and with a superconducting transition temperature of 13.1 K and 15.2 K, respectively. On the other hand, the NbN film grown on the Si substrate exhibits random polycrystalline orientation. Together with the smallest coherent domain size it leads to the lower critical temperature of 8.3 K. Finally, by using a passivation surface layer we are able to improve superconducting properties of NbN thin film and we observe superconducting transition temperature 16.6 K, the one of the highest value reported so far for 50 nm thick NbN film on sapphire.

Superconducting transition temperature of single-phase Tl-2223: Crucial role of Ca-vacancies and Tl-content

1989 ◽  
Vol 160 (2) ◽  
pp. 155-160 ◽  
Author(s):  
R.M. Iyer ◽  
G.M. Phatak ◽  
K. Gangadharan ◽  
M.D. Sastry ◽  
R.M. Kadam ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Crucial Role ◽  
Superconducting Transition Temperature ◽  
Single Phase ◽  
Superconducting Transition

IMPACT OF PRECURSOR SOURCE ON THE STRUCTURAL AND SUPERCONDUCTING PROPERTIES OF (Hg,Cr)Sr2CuO4+δ

2004 ◽  
Vol 18 (30) ◽  
pp. 1517-1524
Author(s):  
S. BALAMURUGAN ◽  
P. SELVAM
Keyword(s):  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Structural Phase ◽  
Superconducting Transition ◽  
Superconducting Properties ◽  
Dc Magnetization ◽  
Ft Ir ◽  
Carbonate Source ◽  
Partial Vacuum

We have investigated the structural/phase and superconducting properties of ( Hg , Cr )/ Sr -1201 [( Hg , Cr ) Sr 2 CuO 4+δ] samples prepared by two different precursor routes. It was observed that the quality of the ( Hg , Cr )/ Sr -1201 samples depends strongly on the precursor quality and the nature of starting materials. The ( Hg , Cr )/ Sr -1201 samples were synthesized in partial vacuum at 1153 K for 12 h, and characterized by power XRD, FT-IR, χ ac -T and dc-magnetization. A good quality ( Hg , Cr )/ Sr -1201 sample with higher superconducting transition temperature [Formula: see text] was obtained for the sample prepared from nitrate source as compared to that obtained from the sample prepared from the carbonate source [Formula: see text].

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