Pinning Energy of High-Tc (Bi, Pb)2Sr2Ca2Cu3Oy

The flux pinning potential energy of silver (Ag) sheathed high-Tc Bi-2223 tapes determined from measured current densities, J(T,H), is reported in this paper. Measurements of the transport current density, J, of the Ag sheathed Bi-2223 tapes were performed with an applied magnetic field directions parallel (H‖ab) and perpendicular (H‖c) to the tape’s board surface from 0 to 3 T, at temperatures from 23 to 77 K. To obtain the pinning potential energy of the Bi-2223 superconductor, an empirical scaling of J(T,H) is introduced in this study. Under the flux dynamics, the effective pinning energy, Ueff(T,H,J), can be formulated using the measured current density, J(T,H). Furthermore, the pinning potential energies, U(T,H), for both H‖ab and H‖c were quantitatively determined by the scaling of J(T,H). The two energies, U(T,H), exhibit as a function that is inversely proportional to both temperature and logarithmic magnetic field. The magnitude of U(T,H) for H‖ab is three or more times larger than that for H‖c under the considered conditions. The U(T,H) is sensitive to the temperature, but insensitive to the magnetic field. This characteristic of insensitiveness towards magnetic field is an advantage for applications on the conditions of high current density, high magnetic field, and low temperature.