Influence of compressive length of normal stress on degradation in Bi-2223 tapes

We have applied transversal-compressive force to typical Bi-2223 tapes with multi-filaments and a Ag-alloy matrix. The degradation of superconducting performance of the tapes against the compressive force was measured. In the experiment, damaged lengths along the tape were changed, and hence, the dependence of the damaged lengths on the I_c degradation were also evaluated. According to the experimental results, in spite of the same stress to the tapes, the I_c degradation clearly depended on the loaded length along the tape. Therefore, the superconducting property degraded with increasing of the damaged length. When the transversal-compressive force is applied to the tape surfaces, it should be carefully noted that the degradation depends on the damaged length along the tape.