ISOTROPIC SHORT COLUMNAR PINNING CENTERS FROM FISSION FRAGMENT DAMAGEIN BULK MELT-TEXTURED YBCO

Uranium, with a controllable amount of U-235, is admired with YBCO, me lt-textured, and irradiated with thermal neutrons, to fission U-235. F ission fragments produce short (similar to 20 mu m), isotropic columna r damage, which act as pinning centers. In samples 2cm in diameter and 0.8cm thick, J(c) of 65000 A/cm(2) and trapped fields similar to 2.1T at 77K have been achieved. A mini-magnet composed of four such sample s traps 3.2T at 77K, and 8.1T at 62K.