Fabrication of high Jc Bi2223 thick films through grain alignment technique using a permanent magnet

In order to realize practical superconducting joints between Bi2223 tapes towards persistent-current magnets, Bi2223 thick films with high critical current density (Jc) suitable for joint intermediate layers are needed. On the other hand, the methodology of c-axis grain alignment for improving the critical current properties in the polycrystalline materials with a relatively large thickness has not been established. Although the magnetic grain alignment technique is known to be effective for Bi2223 materials, there have not been any successful studies achieving high intergrain Jc of Bi2223 polycrystalline materials prepared thorough the magneto-scientific method thus far. In the present study, fabrication and evaluation of the physical properties of the c-axisaligned thick films obtained through grain alignment technique using a permanent magnet were performed. Improvement of the intergrain Jc according to the magnetic grain alignment was confirmed in the thick film samples. Control of the microstructure demonstrated in the present study is one of the promising way for realization of the practical superconducting joints between the Bi2223 commercial tapes.

Automated summary

In order to achieve practical superconducting joints between Bi2223 tapes for persistent-current magnets, high critical current density (Jc) Bi2223 thick films suitable for joint intermediate layers are needed. Despite the effectiveness of magnetic grain alignment technique for Bi2223 materials, successful studies in obtaining high intergrain Jc of Bi2223 polycrystalline materials prepared through magneto-scientific method have not been reported. This study demonstrated the improvement of intergrain Jc in Bi2223 thick films through magnetic grain alignment, showing promise for practical superconducting joints between Bi2223 commercial tapes.