Fabrication and the Characteristics of Silver Sheathed Tl-Ba/Sr-Ca-Cu-O Multi-core Tapes

Multi-core tapes are expected to improve Jc and stability performance for the future actual uses. In the present study silver sheathed Tl-Ba(Sr)-Ca-Cu-O tapes with single, 36 and 1, 332 cores were fabricated with various cross-sectional sizes by rolling or pressing method and their superconducting characteristics were investigated in various conditions. The highest Jc values 14, 500, 8, 600 and 1, 100A/cm2 were attained for the single-, 36- and 1, 332-core tapes with 0.1mm thickness, respectively, at 77K without external magnetic field. Observation of cross-section revealed a non-uniform area of superconducting filaments in multi-core tapes, which degraded the superconducting characteristics of the tapes. The Jc values of multi-core tapes were also measured under external magnetic fields less than 1T. The features of this Tl series oxide superconducting tapes showed that there were no indications of difference of the Jc values in any direction of the magnetic field to the tape surface. Bending tests were carried out with the multi-core tapes. The 36- and 1, 332-core tapes could endure higher strains than the single-core tapes.