2001-2

2) High-Field Intermetallic Compound Superconductors

New (Nb,Ta)₃Sn conductors with attractive high-field performance have been fabricated from Ta-Sn/Nb(Nb-Ta) composites. A thick and uniform (Nb,Ta)₃Sn layer is formed at the interface between the Ta-Sn core and the Nb(Nb-Ta) sheath. When the Ta concentration exceeds 40at%, the Ta-Sn ingot can be crushed into a fine powder and then the powder core process is applied to fabricate the composites. Meanwhile, when the Ta concentration is below 30at%, a ductile Ta-Sn sheet can be prepared and then the Jelly Roll process is applied to fabricate the composites as illustrated in the figure. A non-Cu J_c of 15,000A/cm² is achieved at 22～23T and 4.2K in both the powder core and the Jelly Roll processed wires after an appropriate heat treatment.

Faculty of Engineering,Tokai University : Kyoji Tachikawa, Makoto Aodai,Hiroyuki Izawa
IMR, Tohoku University : Kazuo Watanabe
Reference : K.Tachikawa, T. Kato, H. Matsumoto, R.Kato, T. Takeuchi
"High-field performance and structure of (Nb,Ta)₃Sn superconductors produced by Ta-Sn core",
IEEE Trans. Appl. Supercond. 11 (2001) 3663-3666.