Analysis on Current Distribution in Bi-2223/Ag Tapes with Applied Alternating Over-critical Current

Generally Bi-2223/Ag tapes have a broad S/N transition region and their sheath is a good electric conductor. In this study, the current distribution between superconductor and metal sheath in HTS tapes were investigated. AC with its peak value above 10 times $I_{c}$ was applied to HTS tapes for around 6 cycles and V-I characteristics were measured. Using the resistance of the sheath and V-I curves, the current distribution between superconductor and metal sheath was calculated. When 150 $A_{p}$ was applied, more than 2/3 of the current flows through superconductor. However, in the case of 304 $A_{p}$, most of the applied current came to flow through the metal sheath at the 6th cycle.e.e.e.