Spatial distribution of critical current and supercurrent density in individual filaments extracted from Ag-sheathed Bi-2223 tapes

The critical current density J(c) distributions along individual filaments of Bi-2223/Ag tapes are studied by low-temperature scanning laser microscop y. The filaments are extracted from the tapes by cutting them with a high-p ower UV laser. A relation between the supercurrent density distribution alo ng cross section and the response amplitude is determined. The spatial reso lution of this imaging method for bulk filaments is about few micrometers. (C) 2000 Elsevier Science B.V. All rights reserved.