Pb-free Bi系バルク電流リードの作製とその超電導特性

冷凍機冷却型超電導マグネットへの適用の可能性

抄録

The cylindrical bulk current lead was fabricated using Pb-free Bi system superconductors in a solid-state reaction. The current lead attained a high transport critical-current density (J_c) of about 320A/cm² at 77K, 0T and more than 1, 200A/cm² at 40K, 2T. The Pb-free current lead was composed of both Bi-2223 and Bi-2212 phases judging from the AC susceptibility curve and X-ray diffraction pattern. The heat leakage and mechanical strength of the Pb-free cylindrical bulk current lead were approximately similar to those of a Pb-dope current lead consisting of the Bi-2223 phase only. The Pb-free bulk lead particularly showed a high J_c property at low temperatures and high magnetic field. The Pb-free current lead had the characteristics of both Bi-2212 and Bi-2223 phases. The application of the bulk current lead for a cryocooled superconducting magnet was investigated.