Change of Superconducting Parameters of Y-Ba-Cu-O Slabs and Rings due to High-Energy Ion Beams

2006 ◽  
Vol 47 ◽  
pp. 63-68
Author(s):  
I. Kirschner ◽  
A. Balogh ◽  
Cs. Mészáros ◽  
R. Laiho ◽  
Gy. Kovács ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Magnetic Measurements ◽  
High Energy ◽  
External Irradiation ◽  
High Tc ◽  
Fitting Method ◽  
Properties Of Materials ◽  
Superconducting Parameters

Different high-Tc superconducting Y-Ba-Cu-O samples of slabs and rings have been investigated. Using differently prepared Y1Ba2Cu3O7-d materials, significant deviations between irradiated and unirradiated specimens have been detected in their properties. These investigations demonstrate that unlikely prepared superconductors are differently sensitive to the external irradiation, although they have the same composition. The irradiation applied during these experiments consisted of high-energy Bi-ions with the flux of 5x1010 ions/cm2 and with the energy of 720 MeV. As is experienced, a considerable variation of the magnetic moment in the extent of 19-44% and a significant increase of the critical current density up to 41% can be detected. These originate from the change of the properties of materials due to the irradiation. For the evaluation of the experiments a new fitting method is elaborated for the temperature dependence of the critical current density, providing fully correct results for the whole temperature interval. The A.C. magnetic measurements show, that the irradiation causes to reach the state of the perfect diamagnetism at higher temperatures, than in the case of unirradiated samples. Similarly, the irradiated specimens have much lower losses, than the unirradiated ones and even these smaller values disappear at low temperatures.

STUDY OF THE TEXTURING IN BSCCO-AG TAPES THROUGH MAGNETIC MEASUREMENTS

2000 ◽  
Vol 14 (25n27) ◽  
pp. 3159-3164
Author(s):  
C. FERDEGHINI ◽  
M. R. CIMBERLE ◽  
G. GRASSO ◽  
P. GUASCONI ◽  
A. MALAGOLI ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Magnetic Measurements ◽  
Texture Evolution ◽  
Rolling Direction ◽  
Longitudinal Direction ◽  
Magnetic Method ◽  
Superconducting Compounds

We have developed a method that allows, by a simple set of magnetic measurements, to study the texturing of the grains inside a BSCCO-Ag tape. Because the texture is anisotropic we define the angle ϑ L that identifies the mean grain misalignment angle with respect to the tape surface in longitudinal direction (i.e. rolling direction) and the angle ϑ T in transverse direction. The technique is based on the assumption that, because of the very high anisotropy of the critical current density in BSCCO superconducting compounds, the magnetic moment is essentially generated by the current circulating in the a-b planes of the BSCCO grains. The different magnetisation cycles, measured when the orientation of the magnetic field with respect to the tape surface is changed, depend only on the grain orientation inside the tape, which determines the effective magnetic field component normal to the a-b planes of the grains. Here we present the texture evolution of the BSCCO grains inside silver sheated multifilamentary tape starting from the initial steps of the mechanical deformation up to the final heating stage. The results obtained from the magnetic method are compared with those obtained with other methods, i.e. X-ray diffraction and critical current density anisotropy. Also results obtained on samples prepared in different way will be presented.

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
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