Fabrication and characterization of high T/sub c/ superconducting magnetic shield

Superconducting magnetic shields of Y-Ba-Cu-O superconductor were fabricated in tubular form with one end closed. These shields were used successfully to reduce the flux noises of a two-hole RF SQUID of Y-Ba-Cu-O superconductor. Hysteretic critical current density and penetrated field amplitude under increasing and decreasing magnetic fields reveal the presence of grain boundary weak links. The flux trapping behavior can be explained by using a modified version of C.P. Bean's self-field-limiting model (1962).