Nanoscale pinning media in bulk melt-textured high-t_c superconductors and their importance for super-magnet applications

The creation and control of nanoscale pinning media in melt-processed ternary superconductors (LRE₁,LRE₂,LRE₃)- Ba₂Cu₃O_y (LRE=light rare earth) represent an important issue not only for the bulk form of these superconductors. Some of the nanometre-size defects are able to increase irreversibility field up to 14 T at 77 K, others extend the pinning performance of the material up to vicinity of critical temperature, enabling thus levitation with liquid oxygen or argon cooling. Additionally, an optimum content of MoO₃ doubles the self-field super-current at 77 K, H//c-axis. Altogether, the pinning tailoring in ternary LRE-123 materials provides a flexible and reliable way to fit the electromagnetic performance with the needs of sophisticated high-temperature and high-magnetic-field applications. The research aims at such applications like super-magnets for NMR, drug delivery systems, wind power generation applications, etc. The recent experimental results on ternary LRE-Ba ₂Cu₃O_y materials are reviewed with a special respect to creation and control of novel types of nanoscale pinning media.