Shielding AC magnetic fields using commercial YBa₂Cu₃O₇-coated conductor tapes

High temperature superconducting materials (HTS) offer several advantages in magnetic field shielding applications. HTS materials have the potential of creating efficient shields by reducing the size and weight of the shielding systems. The main limitation until recently has been the difficulty of producing HTS tapes of large width. Recent developments in second-generation (2G) high temperature YBCO superconductors allow the production of 2G films on very large 4 cm wide substrates. Magnetic field shielding properties of coils and sheets fabricated from 4 cm wide YBa2Cu3O7-coated conductors are reported. Shielding properties of shields with multiple layers were measured at liquid nitrogen temperatures. Magnetic field amplitude inside the superconducting shields was measured using Hall probes with a phase-sensitive technique. Efficacy of the shields was characterized at varying field amplitude and frequency. Shielding of up to 95% of applied magnetic field was observed at magnetic field amplitudes of <10 mT. The frequency dependence of shielding properties depended on the geometry of the shields.