Enhancement of the critical current density and the irreversibility field in maleic anhydride doped MgB2 based tapes

Abstract

A significant enhancement of Jc, Hirr, and Hc2 in MgB2 tapes has been achieved by using maleic anhydride (C4H2O3) as dopants. MgB2 tape samples with 0 up to 30wt% C4H2O3 added were prepared by an in situ processed powder-in-tube method. Compared to the pure tapes, Jc for the 10wt% C4H2O3 doped samples was improved by more than an order of magnitude in high fields up to 18T. At 4.2K, the transport Jc for the 10wt% doped samples reached 1.08×104, 5.42×103, and 2.18×103A∕cm2 at 12, 14, and 16T, respectively, and were better than those of the best MgB2∕Fe tapes reported by far. Furthermore, the Hirr for the 10wt% doped sample reached 9.6T at 20K, which was comparable to that of NbTi at 4.2K. The improvement of the superconducting properties in doped tapes can be attributed to the increase of Hc2 and the grain size refinement by C4H2O3 doping.