DocumentCode :
1123393
Title :
Current Transport Mechanism and Control of the 
-Value for Ag/Bi2212 Wires and Tapes
Author :
Awaji, Satoshi ; Inoue, Takushi ; Takahashi, Ken-Ichiro ; Badica, Petre ; Nishijima, Gen ; Watanabe, Kazuo
Author_Institution :
High Field Lab. for Supercond. Mater., Tohoku Univ., Sendai, Japan
Volume :
19
Issue :
3
fYear :
2009
fDate :
6/1/2009 12:00:00 AM
Firstpage :
3071
Lastpage :
3075
Abstract :
In order to study the mechanism of the small n-value for Bi2212, E- J characteristics were measured carefully for various kinds of Bi2212 tapes and round wires in high magnetic fields. Some of wires were heat-treated in a magnetic field of 5 T. We found that the n -values of all the samples increase by the in-field heat-treatment at 5 T. In addition, we analyzed the E- J properties by the combination of the percolation model based on the local Jc distribution and the two directional Jc distribution model. The improvement of the n-value by the in-field heat treatment can be understood by the change of the aspect-ratio of the grains. Therefore, the aspect-ratio of the grains plays an important role in the current transport influencing not only Jc but also n-value.
Keywords :
bismuth compounds; calcium compounds; critical current density (superconductivity); grain size; heat treatment; high-temperature superconductors; magnetic field effects; percolation; silver; strontium compounds; superconducting tapes; Ag-Bi2Sr2CaCu2O8; Bi2212 tapes; E-J characteristics; aspect-ratio; critical current density; current transport mechanism; grain size; in-field heat-treatment; magnetic field effects; magnetic flux density 5 T; n-values; percolation model; superconducting wires; $n$ -value; Bi2212 tape and wires; critical current density; high magnetic field; in-field heat-treatment;
fLanguage :
English
Journal_Title :
Applied Superconductivity, IEEE Transactions on
Publisher :
ieee
ISSN :
1051-8223
Type :
jour
DOI :
10.1109/TASC.2009.2018211
Filename :
5153165
Link To Document :
