The Transport Characteristics and the Self-field Distribution for High-Tc Superconductor with Neighboring Magnetic Materials

Abstract

Many high-Tc superconducting (HTS) tape manufactures make an effort to improve the transport characteristics of HTS tapes. When AC or DC current flows in the HTS tape, AC or DC magnetic self-fields are induced around the conductor by the current and these self-fields affect on the AC loss and the critical current like the transport characteristics of HTS tapes. The spatial distribution and magnitude of the self-field are variable due to the neighboring materials on the HTS tape. In this paper, the relation between the transport characteristics and the self-field distribution of HTS tapes with paralleled ferromagnetic material (Ni tape) and/or diamagnetic material (BSCCO tape) is experimentally investigated. The self-fields according to the DC and AC transport currents were measured by hall probe with axial and radial magnetic field components. The critical currents of HTS tapes with paralleled the Ni tape are slightly decreased and the transport current losses markedly increased. However, the critical currents and transport current losses of HTS tapes with paralleled BSCCO tape showed more improved performance than those of single HTS tape. We explain these results using the change of the spatial distribution and magnitude of self-field on HTS tapes by the neighboring magnetic materials.