Figure 2. Comparison of the superconducting critical current density Jc(H, 4.2 K) of the Bi2223 flat tape and the Bi2212 round wire.
The field H was applied normal to the wire axis for Bi2212, and to the tape face for Bi2223, respectively. The triangles of Bi2212 and Bi2223 indicate Jc measured in increasing field, whereas the circles of Bi2212 and Bi2223 represent Jc in decreasing field. Note that Jc of Bi2212 round wire is approximately 3 times larger than that of the Bi2223 flat tape and is without any field hysteresis, which is quite evident in Bi2223 and is shown more clearly in the inset.