The role of uranium chemistry and uranium fission in obtaining ultra-high Jc in textured Y123

When uranium (U) is added to Y123 powders, after texturing the deposits containing U are found to be ∼300 nm. These deposits act as pinning centres, and increase Jc by 90% per 0.8 wt% U. Neutron irradiation further increases Jc. Total increases of Jc by factors of e.g. ∼30 (at 77 K, 0.25 Tesla), and ∼15 (at 50 K, 10 Tesla) result. Magnitudes of Jc are ∼290,000 A cm-2 (at 77 K, 0.25 T) and 106 A cm-2 (at 50 K, 0.25 T). The U/n process is not yet optimized. Chemistry, microstructure, radiation effects and cost are discussed. (author)