Critical current density distribution in the superconducting oxide layer of pre-annealing and intermediate-rolling processed Bi2Sr2CaCu2Ox/Ag composite tapes

摘要

The critical current density (J(c)) distribution in the oxide layer of PAIR (pre-annealing and intermediate rolling) processed Bi2Sr2CaCu2Ox (Bi-2212)/Ag composite tapes is studied in order to give a clear explanation for the large J(c) enhancement by the PAIR process. J(c) of the oxide layer within 2 mu m from the Bi-2212/Ag interface exceeds 3.8 x 10(5) A cm(-2) at 4.2 K and 10 T. No significant increase of J(c)(local) is confirmed in the Bi-2212 layer at less than 2 mu m from the interface. However, J(c)(local) increases by performing the PAIR process in the middle part of the Bi-2212 layer 2-15 mu m from the interface. J(c)(local) is 2.4 x 10(5) A Cm-2 and 1.0 x 10(5) A Cm-2 at distances of 5 mu m and IO mu m from the interface respectively. The results indicate that the large J(c) enhancement by the PAIR process can be attributed to higher J(c)(local) in this middle part. J(c) improvement in the part near the free surface is also achieved by the PAIR process and contributes to high J(c). [References: 22]