Effect of Magnetic Field on the Critical Current Density of High TC Superconductors

1992 ◽  
Vol 170 (2) ◽  
pp. K99-K102
Author(s):  
Xiao-Guang Li ◽  
Yongwei Song ◽  
Feng Wang ◽  
Shigeng Song ◽  
Rongji Lai ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
High Tc Superconductors ◽  
High Tc

scholarly journals Modification of Critical Current Density Anisotropy in High-Tc Superconductors by Using Heavy-Ion Irradiations

2021 ◽  
Vol 5 (2) ◽  
pp. 16
Author(s):  
Tetsuro Sueyoshi
Keyword(s):  
Magnetic Field ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Ion Irradiation ◽  
Heavy Ion ◽  
High Tc Superconductors ◽  
High Tc ◽  
Heavy Ion Irradiation ◽  
The Magnetic Field

The critical current density Jc, which is a maximum value of zero-resistivity current density, is required to exhibit not only larger value but also lower anisotropy in a magnetic field B for applications of high-Tc superconductors. Heavy-ion irradiation introduces nanometer-scale irradiation tracks, i.e., columnar defects (CDs) into high-Tc superconducting materials, which can modify both the absolute value and the anisotropy of Jc in a controlled manner: the unique structures of CDs, which significantly affect the Jc properties, are engineered by adjusting the irradiation conditions such as the irradiation energy and the incident direction. This paper reviews the modifications of the Jc anisotropy in high-Tc superconductors using CDs installed by heavy-ion irradiations. The direction-dispersion of CDs, which is tuned by the combination of the plural irradiation directions, can provide a variety of the magnetic field angular variations of Jc in high-Tc superconductors: CDs crossing at ±θi relative to the c-axis of YBa2Cu3Oy films induce a broad peak of Jc centered at B || c for θi < ±45°, whereas the crossing angle of θi ≥ ±45° cause not a Jc peak centered at B || c but two peaks of Jc at the irradiation angles. The anisotropy of Jc can also modified by tuning the continuity of CDs: short segmented CDs formed by heavy-ion irradiation with relatively low energy are more effective to improve Jc in a wide magnetic field angular region. The modifications of the Jc anisotropy are discussed on the basis of both structures of CDs and flux line structures depending on the magnetic field directions.

MICROWAVE ABSORPTION STUDIES ON HIGH-Tc SUPERCONDUCTORS AND RELATED MATERIALS VII — ESR OF DPPH COATED ON A THIN BiSrCaCuO FILM FABRICATED ON MgO(100) SUBSTRATE

1992 ◽  
Vol 06 (11) ◽  
pp. 675-682
Author(s):  
K. SUGAWARA ◽  
T. SUGIMOTO ◽  
Y. SHIOHARA ◽  
S. TANAKA
Keyword(s):  
Magnetic Field ◽  
Critical Current Density ◽  
Temperature Dependence ◽  
Microwave Absorption ◽  
Current Density ◽  
Applied Magnetic Field ◽  
High Tc Superconductors ◽  
High Tc ◽  
Absorption Studies ◽  
Mpmg Method

ESR of DPPH coated on a Bi-Sr-Ca-Cu-O (BSCCO) film (350 Å thick) fabricated on MgO(100) substrate by MOCVD was studied. Temperature dependence of the ESR peak-to-peak linewidth, ΔH pp , and the effect of applied magnetic field on ΔH pp have been studied below about 100 K. The results were compared with those of ESR of DPPH coated on ceramic Y-Ba-Cu-O samples (powder and bulk) made by the MPMG method. The DPPH ESR for the BSCCO film revealed that ΔH pp was independent of applied magnetic field up to about 9 kG. In addition, no similarity between the temperature dependence of the excess ESR linewidth of the DPPH and that of critical current density was found for the BSCCO film. These results for the BSCCO film are different from those for the MPMG YBCO 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.

scholarly journals Dependence of critical current density on microstructure and processing of high-Tc superconductors

1994 ◽  
Vol 23 (11) ◽  
pp. 1191-1197 ◽  
Author(s):  
A. Goyal ◽  
E. D. Specht ◽  
Z. L. Wang ◽  
D. M. Kroeger ◽  
J. A. Sutliff ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
High Tc Superconductors ◽  
High Tc

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.

Sign in / Sign up

Export Citation Format

Share Document