Superconducting Properties of Bi-2212 Multifilamentary Round Wires With Double Layered Core Filaments

Multifilamentary Ag-sheathed Bi-2212 round-shaped wires with double layered core-filaments and AgCu alloy sheathed Bi-2212 round wires were fabricated by the powder in tube technique. Composites consisting of Ag outer sheath and the filaments with number of 7, 37 and 61 and a composite of AgCu alloy outer sheath having 37 and 61 filaments were drawn into wires of 1mm in diameter. The wires were heat treated by a conventional partial-melting process. High oxide core ratio of ∼50% to wire-cross-sectional area could realize high overall critical current densities (Jc) of 280A/mm2 at 4.2K, 10T in Ag sheathed wires with 61-filaments and Jc of 310A/mm2 in AgCu alloy sheathed wires with 37-filaments.