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Flux pinning in Ag-clad (BI, PB)(2)Sr2Ca2Cu3o10+y tape

The resistance of a well-characterized Ag-clad (Bi, Pb)(2)Sr2Ca2CU3O10+y (hereafter Bi2223) tape containing about 2% of Bi22 12 phase has been measured in the temperature (T) range 77-120K and magnetic field (B) up to 1T. The measurements were performed on two sections of the same tape showing very different critical current densities (J(ct)(77K0T)=6 100(S-A) and 23 000 A/cm(2) (S-B), respectively) as well as on a bare core of sample S-B. All resistances showed an initial exp(-U(T, B)/k(B)T) variation enabling the determination of the pinning potential U(T, B). The values of U-0(B)drop V(T-->0, B) were nearly the same for all samples and showed rather modest anisotropy for B perpendicular to c and B parallel to c consistent with the imperfect grain alignment in the studied tape. Since U-0(B) of the tape is larger than those of the best Bi2212 and Bi2223 epitaxial films the intragranular flux pinning is not limiting J(c) of Bi2223 tapes in low fields

Ag-clad (Bi, Pb)2Sr2Ca2Cu3O10+y

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