Superconducting butt joint of Bi-2212/Ag multi filamentary tapes

Superconducting properties of butt joints for Bi-2212/Ag multifilamentary tapes were studied in relation to the crystal orientation. The multifilamentary Bi-2212/Ag tapes with 19 and 55 filaments were prepared by a powder-in-tube technique. The tapes were butt jointed, followed by partial melting in a flowing oxygen atmosphere. The typical dimensions of the tapes used in the experiments were 3-5 mm in width, 0.15-0.25mm in thickness, and 30-40mm in length. The critical current Ic of the joint reached around 500A, showing a high possibility for use in persistent magnets. The crystal alignment of the butt jointed tape was analysed by means of a transmission X-ray diffraction method, and it was found that the preferred orientation was observed with in the joint. The marked angular dependence of Jc of the joint also proved the excellent c-axis alignment.