GENERATION OF 1T, 0.5HZ ALTERNATING MAGNETIC-FIELD IN ROOM-TEMPERATURE BORE OF CRYOCOOLER-COOLED BI-2212 SUPERCONDUCTING MAGNET

Alternating magnetic fields have been stably generated at frequencies up to 0.5 Hz in a room temperature (RT) bore of a Bi-2212 superconduct ing magnet cooled by a Gifford-McMahon (G-M) cryocooler. The magnet ha s generated alternating magnetic fields with peak magnetic fields up t o 1.0 T. The present Bi-2212 superconducting coil heat-treated in an o xygen partial pressure (pO(2)) of 1 atm has shown an alternating curre nt (a.c.) loss characteristic, reducing the intergranular hysteresis l oss compared with the heat treatment in pO(2) of 0.2 atm. (C) 1996 Els evier Science Limited