抄録
Superconducting properties were discussed in connection with microstructure for the grain oriented Bi-based high- and low-Tc tapes prepared by both Ag sheath method and doctor blade method. For the high-Tc tapes, grain oriented microstructure was obtained by applying the combination of cold rolling and sintering. For the low-Tc tapes, on the other hand, grain orientation was attained by the partial melting method. Critical current density Jc was significantly improved by the grain orientation for both high- and low-Tc tapes. Especially, the low-Tc tapes show excellent coupling properties of grains, leading to the large Jc above 104A/cm2 at 77K and zero magnetic field. However, at 77K, magnetic field dependence of Jc was very large both for high- and low-Tc tapes. At 4.2K, on the other hand, Jc was much less sensitive to magnetic field. Maximum Jc at 4.2K was 9×104A/cm2 at 10T and 6.8×104A/cm2 at 23T for low-Tc tapes prepared by the doctor blade method. The results indicate that grain oriented Bi-based oxide superconductor is very promising for the high field superconducting magnet.
