Angular Dependence of Critical Current and Grain Alignment in Bi-2223 Superconducting Joint

We clarify the relationship between the angular dependence of critical current in a Bi-2223 superconducting joint and the grain alignment of an intermediate layer in the joint. The angular dependence of critical current for the superconducting joint is discussed using a model to describe that for a Bi-2223 tape. Considering an angle of the c-axis grain misalignment, the angular dependence is calculated. The misalignment angle is validated from the microstructure observations of the intermediate layer. We can conclude that the c-axis grain alignment in the intermediate layer dominates the angular dependence of critical current in the superconducting joint.