scholarly journals Influence of Carbon Content on Superconductivity of Bi2Sr2CaCu2Ox

2017 ◽  
Vol 5 (1) ◽  
pp. 77
Author(s):  
Deawha Soh ◽  
Zhanguo Fan ◽  
N. Korobova
Keyword(s):  
Solid State ◽  
Grain Boundary ◽  
Critical Current Density ◽  
Carbon Content ◽  
Critical Current ◽  
Conventional Method ◽  
Current Density ◽  
Solid State Reaction ◽  
Sintering Process ◽  
Shs Method

<p>Bi<sub>2</sub>Sr<sub>2</sub>CaCu<sub>2</sub>O<sub>X</sub> was prepared by the conventional method of solid state reaction and SHS method. The samples were annealed in different atmosphere in order to examine the influence of atmospheres on the carbon contents in the Bi<sub>2</sub>Sr<sub>2</sub>CaCu<sub>2</sub>O<sub>X</sub> compound. The lowest carbon content in Bi<sub>2</sub>Sr<sub>2</sub>CaCu<sub>2</sub>O<sub>X</sub> could be attended when the sample was annealed in O<sub>2</sub> at 800 °C for 100 hours. The CO<sub>2</sub> in air pollute the samples and increase the carbon content in the sintering process. The critical current density of the Bi<sub>2</sub>Sr<sub>2</sub>CaCu<sub>2</sub>O<sub>X</sub> samples will decrease with the increasing carbon contents in the samples. The impurity carbon will deposit in the grain boundary, which makes critical current density lower.</p>

scholarly journals Effect of Heat Treatments under High Isostatic Pressure on the Transport Critical Current Density at 4.2 K and 20 K in Doped and Undoped MgB2 Wires

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5152
Author(s):  
Daniel Gajda ◽  
Andrzej J. Zaleski ◽  
Andrzej J. Morawski ◽  
Malgorzata Małecka ◽  
Konstantin Nenkov ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Solid State ◽  
Thermal Treatment ◽  
Magnetic Fields ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Solid State Reaction ◽  
Transport Critical Current Density ◽  
Mgb2 Wires

Annealing undoped MgB2 wires under high isostatic pressure (HIP) increases transport critical current density (Jtc) by 10% at 4.2 K in range magnetic fields from 4 T to 12 T and significantly increases Jtc by 25% in range magnetic fields from 2 T to 4 T and does not increase Jtc above 4 T at 20 K. Further research shows that a large amount of 10% SiC admixture and thermal treatment under a high isostatic pressure of 1 GPa significantly increases the Jtc by 40% at 4.2 K in magnetic fields above 6 T and reduces Jtc by one order at 20 K in MgB2 wires. Additionally, our research showed that heat treatment under high isostatic pressure is more evident in wires with smaller diameters, as it greatly increases the density of MgB2 material and the number of connections between grains compared to MgB2 wires with larger diameters, but only during the Mg solid-state reaction. In addition, our study indicates that smaller wire diameters and high isostatic pressure do not lead to a higher density of MgB2 material and more connections between grains during the liquid-state Mg reaction.

EFFECTS OF Gd DOPING IN YBa2Cu3O7-delta ON THE CRITICAL CURRENT DENSITY

2007 ◽  
Vol 21 (18n19) ◽  
pp. 3216-3219 ◽  
Author(s):  
S. XU ◽  
X. S. WU ◽  
G. B. MA ◽  
M. LIU
Keyword(s):  
Critical Temperature ◽  
Solid State ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Solid State Reaction ◽  
Applied Field ◽  
Unit Cell ◽  
Rietveld Refinements ◽  
Resistivity Measurements

Gd is successfully embedded into YBa 2 Cu 3 O 7-δ by the solid state reaction. Rietveld refinements show that Gd replaces Cu in the unit cell. By magnetization and resistivity measurements, the effects of Gd -doping in YBCO on the critical current density J c and the critical temperature T c in YBa 2 Cu 3 O 7-δ( YBCO ) have been investigated. J c varies with the applied field and the content of Gd and has a maximum at x = 0.03. The characteristic behavior of J c with varying the Gd content can be explained in terms of the competition between two different effects caused by Gd -doping in YBCO: the inhomogeneity of grains distribution in nano-scale and the variation of superconductivity.

scholarly journals Critical Current Density Limitation of LLZO Solid Electrolyte: Microstructure versus Interface

2021 ◽  
Author(s):  
Thibaut Dussart ◽  
Nicolas Rividi ◽  
Michel Fialin ◽  
gwenaelle toussaint ◽  
Philippe Stevens ◽  
...  
Keyword(s):  
Solid State ◽  
Ionic Conductivity ◽  
Grain Boundary ◽  
Critical Current Density ◽  
Solid Electrolyte ◽  
Critical Current ◽  
Current Density ◽  
Electronic Conductivity ◽  
Applied Pressure ◽  
The Impact

Abstract Al-doped Li7La3Zr2O12 (LLZO) solid electrolyte is a promising candidate for all-solid-state lithium battery (ASSB) due to its high ionic conductivity and stability against lithium metal. Dense LLZO pellets were prepared by high-temperature sintering and a Li3BO3 melting agent was used to control the microstructure (grain size and grain boundary chemistry). An ionic conductivity of 0.49 mS.cm-1 was measured at room temperature. The LLZO/Li interface was modified by introducing an aluminum layer. The impact of the microstructure of LLZO ceramics and the chemistry of the LLZO/Li interface were discussed by measuring the critical current density (CCD). Even though secondary phases at the grain boundary lead to an increase of the electronic conductivity, no significant influence of the microstructure on the CCD value (50 micronA.cm-2) has been established. The low CCD value has been improved by forming an Al-Li alloy interlayer at the LLZO/Li interface, due to a better homogenization of the Li current at the interface. In parallel, the applied pressure (0.09 MPa vs. 0.4 MPa) has been studied and did impact the CCD. A value of 0.35 micronA.cm-2 was measured. These results highlight the conditions needed for keeping a good electrolyte/Li interface during the cycling of a solid state battery.

Facet Topography and Dislocation Structure as a Possible Source for Electrical Heterogeneity in [001] TILT Bicrystals of YBa2Cu3O7-δ

1996 ◽  
Vol 54 ◽  
pp. 338-339
Author(s):  
I-Fei Tsu ◽  
D.L. Kaiser ◽  
S.E. Babcock
Keyword(s):  
Grain Boundary ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Electromagnetic Properties ◽  
Length Scale ◽  
Density Values ◽  
Current Densities ◽  
Applied Fields ◽  
A Current

A current theme in the study of the critical current density behavior of YBa2Cu3O7-δ (YBCO) grain boundaries is that their electromagnetic properties are heterogeneous on various length scales ranging from 10s of microns to ˜ 1 Å. Recently, combined electromagnetic and TEM studies on four flux-grown bicrystals have demonstrated a direct correlation between the length scale of the boundaries’ saw-tooth facet configurations and the apparent length scale of the electrical heterogeneity. In that work, enhanced critical current densities are observed at applied fields where the facet period is commensurate with the spacing of the Abrikosov flux vortices which must be pinned if higher critical current density values are recorded. To understand the microstructural origin of the flux pinning, the grain boundary topography and grain boundary dislocation (GBD) network structure of [001] tilt YBCO bicrystals were studied by TEM and HRTEM.

Increased grain boundary critical current density Jcgb by Pr-doping in pulsed laser–deposited Y1−xPrxBCO thin films

2011 ◽  
Vol 110 (11) ◽  
pp. 113905 ◽  
Author(s):  
M. Irjala ◽  
H. Huhtinen ◽  
V. P. S. Awana ◽  
M. Falter ◽  
P. Paturi
Keyword(s):  
Thin Films ◽  
Grain Boundary ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Pulsed Laser

Grain Boundary Structure and Properties of High-Tc Superconductors

1992 ◽  
Vol 275 ◽  
Author(s):  
K. Jagannadham ◽  
J. Narayan
Keyword(s):  
Grain Boundary ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Boundary Effects ◽  
Boundary Structure ◽  
Excess Charge ◽  
High Tc Superconductors ◽  
High Tc ◽  
Grain Boundary Structure

ABSTRACTWe have modelled the grain boundaries in high-Tc superconducting oxides and determined the critical current density. The tunneling of superconducting pairs across the coalesced regions is used to determine the boundary effects. The length of the coalesced regions, with continuity of the Cu-O planes maintained by relaxation of the atom positions, is determined by minimization of the energy of the configuration. The depression of the order parameter is evaluated using the continuity conditions at the boundary in the proximity effect formulation. The excess charge distribution at the core of the boundary, determined from the solution to the Poisson's equation, is used to determine the scattering of the superconducting pairs. The width of the boundary, evaluated from modelling, determines the transmission coefficient for tunnelingof superconducting pairs. The critical current density is expressed in terms of these four important factors associated with the grain boundary. All the experimental results are explained by the present modelling of the grain boundary effects.

Grain boundary microstructure and transport critical current density in YBa2Cu3Ox

1992 ◽  
Author(s):  
Donglu Shi ◽  
Yufei Gao ◽  
A. C. Biondo ◽  
J. G. Chen ◽  
K. L. Merkle ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Transport Critical Current Density ◽  
Boundary Microstructure
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