SUPERCONDUCTING PROPERTIES OF TEXTURED BI-SR-CA-CU-O TAPES PREPARED BY APPLYING DOCTOR BLADE CASTING

Superconducting properties are discussed in connection with microstructure for grain oriented Ag/Bi2Sr2Ca1Cu2Ox (2212) and Bi2Sr2Ca2Cu3Oy (2223) tapes prepared by applying a doctor blade casting method. A.c. susceptibility and d.c. magnetization measurements indicate that the coupling between grains is significantly improved by grain orientation for both tapes. In particular, for the 2212 tape, weak coupling is not observed, and the tape has excellent transport Jc > 104 A cm-2 at 77 K and zero magnetic field. However, at 77 K, the magnetic field dependence of Jc is very large. At temperatures < 20 K, Jc is much less sensitive to magnetic field and excellent Jc-B properties were obtained. The 2212 tapes show transport Jc values well above 105 A cm-2 at 4.2 K in 25 T and 5 × 104 A cm-2 at 20 K in 12 T. The results indicate that the tapes are promising for practical application with liquid helium or liquid hydrogen as coolant. © 1990.