Longitudinal Magnetic Field Effect in Critical Current Characteristics of Bi-2223 Superconducting Tape

摘要

In this study, we concentrated on the longitudinal magnetic field effect in critical current densities and investigated the enhancement of the electrical conduction properties in a commercial Bi-2223 superconducting tape. Since the samples used in this study were polycrystalline and tape-shaped, the variation of the critical current density caused by the longitudinal magnetic field effect and anisotropy of the upper critical magnetic field was expected to be clarified. Therefore, the critical current characteristics at a magnetic field of up to 5 T as well as at various angles between the magnetic field and current were measured in detail. Through investigation, more detailed electrical characteristics of Bi-2223 were clarified which can provide superconducting cable developer with more useful information. The results demonstrate the longitudinal magnetic field effect is obvious at the high magnetic field rather than that at the low magnetic field and the upper critical magnetic field is decreasing gradually with the increase of the temperature. It also can be known that the difference between the value of upper critical magnetic field and that of applied magnetic field will exert an influence on the critical current density of Bi-2223 superconducting tape.