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The microstructures and superconducting properties of the (Bi,Pb)2Sr2Ca2Cu3Ox superconductor (following, Bi,Pb–2223) fabricated by a multilayered precursor and a post-annealing process have been investigated in order to obtain high performance Bi-2223 wires and tapes using two kinds of sputtering targets of nominal compositions of Bi,Pb-2212 and CaCuPbO. We fabricated a alternately layered film as a precursor of Bi,Pb-2223. Alternately layered precursor film was annealed within Bi,Pb-2223 pellets at 840oC for various time. After the annealing, we measured the Tc by resistivity and magnetization measurements. The Tc values by the four probe method reached Tczero = 101 K for the 100 hours annealing.
The as-deposited multilayer film epitaxially grown on a (100) SrTiO3(STO) substrate consisted of 30 nm thickness of Bi-2212 phase and 5-10 nm thickness of Ca-layer and CuO2-layer without BiO and SrO layers. Furthermore, there were large grains of Ca and Cu-rich compositions. After 10 hours annealing, there were heterogeneous microstructure composed of the layered structure of the as–deposited film remained and domains where Bi-2212 phase transformed to Bi-2223 phase. After 100 hours annealing, Bi-2223 domains expanded from interface of the STO substrate to the film surface. However, there were still non-superconducting domains in the Bi-2223 film. The volume fraction of Bi-2223 phase in the superconducting region was approximately 50%. It is a future issue to find the optimum condition to obtain the Bi-2223 single phases.