FABRICATION OF 90-M LENGTH BI2SR2CACU2O8+X AG-SHEATHED SUPERCONDUCTING TAPES

Initial results of a 90-m length Ag-sheathed Bi2Sr2Ca1Cu2O8+x (Bi-2212) tape prepared by the oxide-powder-in-tub method are described. The transport J(c) of one 90-m length tape measured in 10-m length sections was similar to 20,000 A/cm(2) at 4.2 K. The J(c) of this tape was reduced to similar to 40% of expected values because the tape was processed in close contact with a ceramic cloth, rather than freestanding. Transport J(c)s of 10-m sections of the 90-m length tape were uniform within similar to 10% variation. Unique problems that must be addressed to obtain uniform property, 90-m length tapes include: (i) bubble defect formations, (ii) similar to 2 cm interval ''kinks'', and (iii) effusion of melted oxides out of the Agsheathed tape. Possible solutions to these problems are suggested.