Transport Critical Current Density in Single-Core Composite Ba122 Superconducting Tapes

We fabricate a 1-meter-long AgSn-stainless steel composite superconducting tape via a flat rolling process. The transport critical current density Jc at different temperatures and magnetic fields is substantially studied. At 4.2 K and 10 T, the Jc of one short sample cut from the 1-meter-long tape achieves 8 × 10
⁴
A/cm
²
. At 20 K and 10 T, the Jc is also as high as 1.4 × 10
⁴
A/cm
²
. Moreover, the 1-meter-long tape presents good Jc homogeneity with an average value of 7.3 × 10
⁴
A/cm
²
. We also measure the resistance and susceptibility of the tape without peeling off the sheath. Based on our results, we suggest that the high strength stainless steel not only applies high pressure to the inner core after flat-rolling, but also act as a reinforcing layer to sustain good Jc uniformity. We also discuss some drawbacks existing in this method and corresponding solutions.