Construction and performance of BSCCO 2212 coils for use in liquid nitrogen at 64K on an iron yoke in demonstrator devices

The construction of 6 HTS coils from composite tapes of a silver alloy dip-coated with BSCCO 2212 is described. Data are presented on the coil critical currents at temperatures over the range 4.2K to 77.3K, including the results of a measurement in liquid neon. A small magnet constructed from two of the coils generated a peak field of 0.434T at 4.2K. A 'demonstrator' device is described in which the coils are mounted on an iron yoke, are immersed in liquid nitrogen refrigerated to 64K using a novel technique, and provide ampere-turns to generate a magnetic field in the air gap between two room temperature pole-pieces. This apparatus is intended for use in a programme of research to investigate the controllability of superconducting magnets in attractive magnetic levitation applications