Development of Multilayered wire using Bi-based superconductor

Abstract

Muntilayered wires, consisting of Bi-superconducting layers and silver layers, have been developed in order to realize high critical current density (J_c), subject optional wire forms. For instance, a Bi-2212 round wire having J_c=37.4 kA/cm² at 4.2K and 10T; a Bi-2223 tape wire, with a silver ratio of 1.3, measured J_c=21.3 kA/cm² at 77K, OT. Several multilayered wires underwent test of J_c-B characteristic, mechanical property and AC losses, in search for their adaptability to electric power equipment. Moreover, assembling multilayered wires was studied in light of AC and DC characteristics, using conductors, each of which was comprised of tape or round wires. In the last place, two solenoid coils of Bi-2212 round wires and a double-pancake coil of Bi-2223 tape wires were fabricated and found to generate magnetic fields of 1.1T at 4.2K, 0.44T at 18K and 42mT at 77K, respectively; their electromagnetic and thermal behaviors were tested as DC operated.