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 Jc 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.