Superconducting Properties of Bi₂Sr₂CaCu₂O_y Tape Prepared by the Continuous Heat Treatment Technique

Abstract

85m-long Bi₂Sr₂CaCu₂O_y (Bi-2212)/Ag multilayer tape was successful fabricated. The tape was prepared by the slurry-painting technique. The multilayer tape was facricated by stacking three Bi-2212/Ag monolayer tapes prepared by the slurry-painting technique, wrapping them with a Ag foil, and finally giving a continuous heat treatment of partial melting and slow cooling. The continuous heat treatment was done by moving the tape along the temperature gradient in a specially designed pipe furnace. J_c values of the wire were 8 × l0³ A/cm² at 77 K 0T and higher than 1×10 ⁵A/cm² at 4.2K, 12T. The variation of J_c value along the 85m-long tape was within 15%. The multilayer tapes showed good strain tolelance of J_c. J_c values unchanged until the bending strain of 0.7% was applied. A small coil fabricated using the “React & Wind” technique had a J_c value almost equal to that of a short straight sample.