Figure 6. Kramer function plots of the Bi2212 round wire and Bi2223 flat tape, derived from magnetization measurements over the temperature range 15–40 K for Bi2223 in (a) and 10–30 K for Bi2212 in (b).
A considerable linear regime exists for both conductors, which is generally taken to be consistent with a vortex pinning dominated Jc behavior. Δm = m(field down) – m(field up), where m denotes the magnetic moment. Note that the magnetization Jc is proportional to Δm.