Interaction of Abrikosov vortex with grain boundaries near Hc1. I. Potential barriers in polycrystalline high-Tc superconductors

2005 ◽  
Vol 31 (2) ◽  
pp. 116-122 ◽  
Author(s):  
L. V. Belevtsov
Keyword(s):  
Grain Boundaries ◽  
Abrikosov Vortex ◽  
High Tc Superconductors ◽  
High Tc ◽  
Potential Barriers

Doping induced enhancement of the critical currents of grain boundaries in high-Tc superconductors

2000 ◽  
Vol 341-348 ◽  
pp. 1393-1396 ◽  
Author(s):  
J. Mannhart ◽  
H. Bielefeldt ◽  
B. Goetz ◽  
H. Hilgenkamp ◽  
A. Schmehl ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Critical Currents ◽  
High Tc Superconductors ◽  
High Tc

Ac Susceptibility Studies of the High Tc Superconductors: Dissipative Effects in La2.xSrxCuO4-Y and YBa2Cu3O7-Y Systems

1989 ◽  
Vol 169 ◽  
Author(s):  
Xinsheng Ling ◽  
M. E. Filipkowski ◽  
E. K. Heller ◽  
J. I. Budnick
Keyword(s):  
Grain Boundaries ◽  
Order Parameter ◽  
Ac Susceptibility ◽  
Similar Process ◽  
Charge Carrier Density ◽  
High Tc Superconductors ◽  
High Tc ◽  
Spatial Fluctuation ◽  
Dissipative Effects ◽  
Ceramic Samples

AbstractWe have studied the variation of dissipative effects with doping in the high Tc superconductors La2-xSrxCuO4-y and YBa2Cu3O7-y by studying the lossy component of ac susceptibility as a function of temperature. We find relatively strong excess losses at low temperature in both systems, which indicate stronger flux creep at grain boundaries, in lower level doped ceramic samples produced by a similar process. This effect is more significant in the La2-xSrxCuO4-y (214) system than in the YBa2Cu3O7-y(123) system. We suggest that the microscopic mechanisms of weakening of the order parameter in the grain boundaries may be different in the two systems. In the 214 system, as the charge carrier density in the CuO2 planes is reduced, the spatial fluctuation of the order parameter in the CuO2 planes is enhanced. In the 123 system, the initial removal of O from the sample, which weakens the coupling between planes and increases the spatial fluctuation of the order parameter between CuO2 planes. The grain boundaries are degraded in both systems. The degradation in the 214 samples is more significant than in the 123 samples.

INFLUENCE OF GRAIN BOUNDARIES ON THE TRANSPORT CRITICAL CURRENT DENSITY OF HIGH Tc SUPERCONDUCTORS

1991 ◽  
Vol 05 (14n15) ◽  
pp. 993-999 ◽  
Author(s):  
HUIMIN SHAO ◽  
MU LU ◽  
TIANCHANG LU ◽  
XICHUN JIN ◽  
LINJIANG SHEN ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Grain Boundaries ◽  
Critical Current ◽  
Current Density ◽  
Transport Critical Current Density ◽  
High Tc Superconductors ◽  
High Tc ◽  
Preparation Conditions ◽  
Percolation Path ◽  
Superconducting Current

This paper describes our efforts to improve the preparation conditions of YBCO samples and increase their density by doping with Sn, F, or Ag and our analysis of the influence of different grain boundaries on superconducting current. We come to the conclusion that, as the grain boundaries have an insulation layer between them forming Josephson junctions and the metalled grain boundaries form proximity junctions which are kind of weak couplings for superconductors, the current-carrying capacity of samples having such grain boundaries cannot be expected to greatly increase. Only by increasing the density of samples and purifying the grain boundaries can a better percolation path for supercurrent be created, thereby considerably increasing the critical current density.

VORTEX POTENTIAL BARRIERS IN THE GRANULAR SUPERCONDUCTORS

2001 ◽  
Vol 15 (06n07) ◽  
pp. 189-198 ◽  
Author(s):  
LEONID V. BELEVTSOV
Keyword(s):  
Grain Boundary ◽  
Josephson Junction ◽  
Grain Boundaries ◽  
Weak Coupling ◽  
Boundary Effects ◽  
Magnetic Vortex ◽  
Abrikosov Vortex ◽  
Surface Barrier ◽  
Potential Barriers ◽  
Granular Superconductors

The grain-boundary effects the potential barriers for Abrikosov vortex penetration into polycrystalline superconductors are investigated using a model in which the vortex, the grain and the grain boundaries are treated on equal basis. It is shown that the Bean–Livingston surface barrier have some substantial features near the grain boundaries for weak coupling between the grains. The potential barriers for magnetic vortex penetration into a grain from Josephson junction is an order to value of the pinning one in these superconducting materials.

Degradation of high-Tc superconductors by annealing in dry and moist atmospheres

1990 ◽  
Vol 5 (9) ◽  
pp. 1855-1859 ◽  
Author(s):  
W-K. Lee ◽  
A. S. Nowick
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Meissner Effect ◽  
Treatment Temperature ◽  
The Other ◽  
Boundary Phase ◽  
Maximum Effect ◽  
High Tc Superconductors ◽  
High Tc ◽  
Anneal Temperature

A study is made of the effects of annealing both La2−xSrxCuO4 (for x = 0, 0.1, and 0.15) and YBa2Cu3O7 in wet and dry O2 atmospheres at various temperatures between 200 and 930 °C. In the case of La2−xSrxSrCuO4, substantial degradation of resistive properties occurs during annealing in moist O2, the degradation being highest at 200 °C and decreasing as the treatment temperature increases. Since the Meissner effect remains unaffected, it is concluded that degradation is due to the formation of a hydroxide species at grain boundaries, which decomposes as the anneal temperature is increased to 930 °C. In the case of YBa2Cu3O7, on the other hand, moisture does not produce degradation for anneals at 200 °C and above, but severe degradation of resistive behavior does occur for dry O2 anneals, with a maximum effect at 500 °C. It is found that this effect results from a contaminant gas, possibly CO2, absorbed by the furnace when it is open to air. Again, the degradation is due to formation of a grain-boundary phase which decomposes by annealing at 930 °C.

Grain boundaries in high-Tc superconductors: insights and improyements

2000 ◽  
Vol 80 (5) ◽  
pp. 827-834 ◽  
Author(s):  
J. Mannhart ◽  
H. Bielefeldt ◽  
B. Goetz ◽  
H. Hilgenkamp ◽  
A. Schmehl ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
High Tc Superconductors ◽  
High Tc

Enhanced current transport at grain boundaries in high-Tc superconductors

Nature ◽  
2005 ◽  
Vol 435 (7041) ◽  
pp. 475-478 ◽  
Author(s):  
R. F. Klie ◽  
J. P. Buban ◽  
M. Varela ◽  
A. Franceschetti ◽  
C. Jooss ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Current Transport ◽  
High Tc Superconductors ◽  
High Tc

scholarly journals Critical Current of Low-Angle Grain Boundaries in High-Tc Superconductors

2013 ◽  
Vol 7 (2) ◽  
pp. 144-148
Author(s):  
Alexander Kasatkin ◽  
Vadim Tsvetkovskii ◽  
Pavel Borisenko
Keyword(s):  
Grain Boundaries ◽  
Critical Current ◽  
High Tc Superconductors ◽  
High Tc
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