Abstract
Dependence of the critical current density of Bi-2223 superconducting tape on the angle of external magnetic field is investigated theoretically and experimentally. The model proposed here is based on an effective coherence tensor model which can deal with the anisotropy of the coherence length, and has been derived so as to be applicable for the arbitrary angle of the external field. The resulting mathematical expression of the angular dependence of the critical current density shows that the critical current density is dependent only on the normal component of the magnetic field to the tape surface (i.e., the component perpendicular to the ab plane). The measurements of critical current density were made based on the four-point DC method, and the results show the validity of the theoretical considerations.
