The critical current characteristic of Y-Ba-Cu-O specimen prepared by the quench-and-melt growth (QMG) technique was investigated by the ac-inductive method. It was found that there were two kinds of currents. The bulk critical current density is 1.0 × 108 A/m2 at 77 K and 0.12 T. This value is comparable to a previous estimate from dc-magnetization measurements. The local current density amounts to 3.2 × 1010 A/m2 under the same conditions. Appearance of two kinds of currents seems to be caused by nonsuperconducting second-phase layers formed along the direction of grain growth, which disturb uniform current.
|Number of pages||4|
|Journal||Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers|
|Publication status||Published - 1989 Sep|
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)