High-transport critical current density above 30 K in pure Fe-clad MgB2 tape
Fe-clad MgB2 long tapes have been fabricated using a powder-in-tube technique. An Mg+2B mixture was used as the central conductor core and reacted in situ to form MgB2. The tapes were sintered in pure Ar at 800°C for 1 h at ambient pressure. SEM shows a highly dense core with a large grain size of 100 μm. The Fe-clad tape shows a sharp transition with transition width of ΔTc of 0.2 K and a Tc0 of 37.5 K. We have achieved the highest transport critical current reported so far at 1.7×104 A/cm2 for both 29.5 K in 1 T and 33 K in zero applied field. Resistivity temperature dependence and transport critical current were also measured in magnetic fields applied perpendicular and parallel to the tape plane. Not only is the use of an Fe sheath necessary for the successful processing of in situ reacted powder-in-tube MgB2, it confers on the finished wire the additional benefit of magnetic screening.
S. Soltanian, X. L. Wang, I. Kusevic, E. Babic, A. H. Li, M. J. Qin, J. Horvat, H. K. Liu, E. W. Collings, E. Lee, M. D. Sumption, and S. X. Dou. "High-transport critical current density above 30 K in pure Fe-clad MgB2 tape" Physica C: Superconductivity and its Applications 361.2 (2001): 84-90.
Available at: http://works.bepress.com/sxdou/98