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 superconducting magnet cooled by a Gifford-McMahon (G-M) cryocooler. The magnet has generated alternating magnetic fields with peak magnetic fields up to 1.0 T. The present Bi-2212 superconducting coil heat-treated in an oxygen partial pressure (pO(2)) of 1 atm has shown an alternating current (a.c.) loss characteristic, reducing the intergranular hysteresis loss compared with the heat treatment in pO(2) of 0.2 atm. (C) 1996 Elsevier Science Limited