Abstract Body

To fabricate larger RE-Ba-Cu-O (RE: rare earth elements) bulk superconductor and/or suitable bulk for pulse magnetization, we have studied the effects of various joining conditions by local melting method on the improvement of the superconducting properties at the joint.   Although the local melting method enables high-quality superconducting joints, it is known that many defects like pores and segregation of the second phase remained at the joint part depending on the fabrication conditions, such as the joining direction and local melting conditions, resulting in a decrease in the superconducting properties.

In this study, we investigated the effects of oxygen atmosphere and local melting conditions (joining direction, melt temperature, time, and cooling rate) on microstructure and superconducting properties (critical temperature and critical current density) of Gd (and Y)-Ba-Cu-O bulk superconductors joined using the local melt growth method in Er-Ba-Cu-O bulk.   As a result, it was found that joining in a high oxygen atmosphere reduces pores, and that high-speed growth reduces segregation and improves the J_c-B properties of the joined parts.  This fabrication method has the potential to produce high-strength, high-performance superconducting joined bulk superconductors.

Keywords: RE-Ba-Cu-O bulk superconductor, superconducting joint, oxygen atmosphere, pore

Figure 1. J_c -B properties of the RE-Ba-Cu-O bulk superconductors with different joining conditions.