Superconducting joint of multifilamentary Bi(Pb)-Sr-Ca-Cu-O tapes

We joined BSCCO(2223) multifilamentary tapes and evaluated their electrical and mechanical properties. In the process, two superconducting-joint methods were used; one is direct connection of two multifilamentary tapes (MM-joint), and the other is connection of them by using one or two single filamentary tape (MSM-) and double-MSM- joint. The critical current ratio (CCR) and n-value of the jointed tapes were evaluated as a function of uniaxial pressure. It was observed that the CCR and nvalue were 24.8-29.0% and 2.5-2.8, respectively, for MM-jointed tape. On the other hand, the corresponding values were improved to 24.8-53.9% and 2.9-4.1 for MSM- and 63.4-76.0% and 3.5-5.1 for double-MSM-jointed tape, respectively. The highest electrical properties of double-MSM-joint are considered to be due to the presence of single core, resulting in better interconnections of multifilaments between the two tapes. The mechanical property of jointed tape was also evaluated and correlated to the microstructural evolution.