Pulsed Field Magnetization of Bridge-Seeded Bulk YBCO Using Solenoid and Split Coils

The multi-seeding process has the potential to enlarge the sample size of (RE)BCO (where RE = rare earth or Y) single-grain bulk superconductors with improved fabrication speed, and in previous studies on multi-seeding, a significant improvement was made in the alignment of the seeds in such samples using a novel bridge-seeding technique. In this paper, we report the experimental measurements of the pulsed field magnetization (PFM) of a 0°-0° bridge-seeded Y-Ba-Cu-O (YBCO) sample. The PFM is carried out using a solenoid coil, as well as a split coil arrangement with an iron yoke, at temperatures of 65, 40, and 20 K, and the resultant trapped fields and magnetic flux dynamics for these two PFM techniques are compared. It is shown that such bridge-seeded bulk YBCO can be fabricated that performs as a bulk magnet with trapped fields comparable to or better than standard, single-seeded high-Jc samples, with the potential of enlarging the sample size. Furthermore, the split coil arrangement with an iron yoke is useful to enhance the trapped field and has a positive effect on the maximum temperature rise in the sample, which increases at lower temperatures and seriously impacts the achievable trapped field from PFM.