Mass Production of Low-Cost GdBaCuO Bulk Superconductors Using a Novel Seed in the Batch Process

We developed a batch process with cold seeding, which considerably reduces the production cost. This batch process is appropriate for fabrication of various LREBa₂Cu₃O_y (where LRE represents a light rare earth element) compounds as it employs novel thin film Nd-123 seeds grown on MgO crystals, compatible with all LRE-123 materials. In the first stage we are able to fabricate GdBa₂Cu₃O_y compound with large single grain, enhanced pinning, and good quality at a dramatically reduced cost. Magnetization results conformed that the samples have a sharp superconducting transition (around 1 K wide) with the onset T_c around 93.5 K. The self-field J_c of 72 kA/cm² was achieved at 77 K, H//c-axis in various positions of the pellet. The trapped field measurements showed that the samples were single-domain and of good pinning performance. The trapped field observed in the best 45 mm single-grain puck of Gd-123 was in the range of 1.35T and 0.35 T at 77.3 K and 87.3 K, respectively. The batch process technology for production of melt-processed LRE-123 provides a cost-effective method to fabricate high-performance super- conducting super-magnets for various commercial applications.