Transport Critical Current Density of Bi-2223 Tape

Abstract

In the power applications of superconductors, the most important key element is the high-temperature superconducting tapes. The essential conditions for superconducting tapes are a high transport critical current density (J_c), shape uniformity of long-length tape and mechanical performance. From these points of view, Bi-2223 superconducting tapes have been considered promising. Short-length tapes with J_c of 40kA/cm² and tapes over 1km in length with J_c of 20kA/cm² have been obtained at 77K. In order to attain higher J_c values, we must consider the content of the Bi-2223 phase, grain alignment, grain connectivity and pinning as important factors of limitation. With the objective to identify the most important factor of limitation, we investigated tapes in detail by XRD, SEM, SQUID and so on.