Magnetic shielding up to 0.67 T at 77 K using a stack of high temperature superconducting tape annuli of 26 mm bore

Abstract In this work we demonstrate the magnetic shielding ability of a stack of YBa2Cu3O7 tape annuli. The annuli are cut from a 46 mm wide second generation coated conductor deposited on a Ni-5at.%W alloy ferromagnetic (FM) substrate. The inner bore of the stacked tapes is 26 mm and the outer diameter is 45 mm. Three samples with different height (24 mm, 14.9 mm, 9.9 mm) are studied. All the experiments are carried out at both room temperature and liquid nitrogen temperature (77 K). The shielding efficiency is investigated when the magnetic field is applied either parallel to the axis of the stack (axial shielding) or perpendicular to it (transverse shielding). Under an axial field, magnetic shielding is found to be effective (SF > 3 ) up to magnetic flux densities of 0.67 T. The presence of the FM substrates is found to have two important consequences. First, the stack of annuli is a…