Microstructure and critical current properties of Bi(Pb)2212/metal tapes and single crystals

Flux pinning mechanism of the heavily lead-doped Bi(Pb)2212 single crystals was studied by the magneto-optical method. Largely different behaviors of J(c) (parallel toa) and J(c) (parallel tob) suggested that temperature-indu ced planar pinning site contributes to the excellent J(c), performance at h igh temperatures in magnetic field. For the Bi(Pb)2212/metal tapes, microst ructure of superconducting layer was improved by addition of MgO fine parti cles or applying the amorphous to crystallization method. However, their tr ansport J(c)'s were still low compared with the lead-free Bi2212/Ag tapes. (C) 2001 Elsevier Science B.V. All rights reserved.