Tilt angle dependences of vortex structure and critical current density at low-angle grain boundaries inYBa2Cu3O7−xfilms

2008 ◽  
Vol 77 (13) ◽  
Author(s):  
Tomoya Horide ◽  
Kaname Matsumoto ◽  
Yutaka Yoshida ◽  
Masashi Mukaida ◽  
Ataru Ichinose ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Grain Boundaries ◽  
Critical Current ◽  
Current Density ◽  
Tilt Angle ◽  
Vortex Structure

Grain Boundaries and Critical Current Density of YBa2Cu3O7-y Thick Film Prepared by Liquid Phase Epitaxy

1996 ◽  
pp. 775-778
Author(s):  
Tasuku Kitamura ◽  
Jian-Guo Wen ◽  
Yuh Shiohara ◽  
Naoki Koshizuka ◽  
Izumi Hlrabayashi ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Critical Current Density ◽  
Grain Boundaries ◽  
Thick Film ◽  
Critical Current ◽  
Current Density ◽  
Liquid Phase Epitaxy

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.

TEM Characterization of Grain Boundary Structure in YBCO Coated Conductors

2000 ◽  
Vol 6 (S2) ◽  
pp. 394-395
Author(s):  
H. Kung ◽  
J.P. Hirth ◽  
S.R. Foltyn ◽  
P.N. Arendt ◽  
Q.X. Jia ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Critical Current Density ◽  
Grain Boundaries ◽  
Critical Current ◽  
Current Density ◽  
Lattice Mismatch ◽  
Coupling Effect ◽  
High Temperature Superconductors ◽  
Coated Conductors ◽  
Boundary Structure

Studies of defects, such as grain boundaries, in high temperature superconductors (HTS) are important due to the interaction of the defects with flux-bearing vortices. The benefit of in-plane grain alignment has been documented in YBCO thin film bicrystals, in which the high critical current density (Jc) observed across small angle grain boundaries deteriorates exponentially with grain boundary angles beyond ∼ 7°. In addition to the weak coupling effect, a grain boundary may also influence the transport properties via the grain boundary dislocations (GBDs) serving as pinning centers to increase the critical current density. There have been a number of studies on grain boundary structures in YBCO. Despite many differences in structure among the different types of boundaries, it has been established that the low angle [001] tilt boundary in YBCO consists of aperiodic array of edge type GBDs with [100] type Burgers vector that accommodate the lattice mismatch, and the regions between the GBDs are channels of relatively undisturbed lattices [1].

Microtexture Mapping of Elecrtron Backscattered Diffraction in (Bi,Pb)2Sr2Ca2Cu3O10 Superconductor Tapes

2000 ◽  
Vol 659 ◽  
Author(s):  
Sean Li ◽  
Thiam Teck Tan
Keyword(s):  
Critical Current Density ◽  
Grain Boundaries ◽  
Critical Current ◽  
Current Density ◽  
Crystallographic Orientation ◽  
Weak Link ◽  
Large Angle ◽  
Orientation Distribution ◽  
Weak Links ◽  
Electron Backscattered Diffraction

ABSTRACTGrain boundaries is believed to act as weak-links limiting the critical current density (Jc) of bulk high-Tcsuperconductors. The weak-link problem can be greatly reduced by elimination or minimization of the large-angle grain boundaries. It has been reported that the Jc distribution in the transverse cross-section of (Bi,Pb)2Sr2Ca2Cu3O10+x (Bi2223) superconductor tapes follows a parabolic relationship, with the lowest currents occurring at the center of the tapes. The Jc distribution is proposed to be strongly dependent on the local crystallographic orientation distribution of the Bi2223 oxides. However, the local three dimensional crystallographic orientation distribution of Bi2223 crystals in (Bi,Pb)2Sr2Ca2Cu3O10+×superconductor tapes has not been experimentally determined yet. In this work, Electron Backscattered Diffraction technique was employed to map the crystallographic orientation of the crystals in Bi2223 superconductor tapes. From this, the misorientation of grain boundaries and also their distribution are obtained. Through crystallographic orientation mapping, the relationship of the crystallographic orientation distribution, the boundary misorientation distribution and the fabrication parameters may be understood. This can be used to optimize the fabrication processes thus increasing the critical current density in Bi2223 superconductor tapes.

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