Significantly enhanced critical current densities in MgB2 tapes made by a scaleable nanocarbon addition route -: art. no. 072502

Nanocarbon-doped Fe-sheathed MgB2 tapes with different doping levels were prepared by the in situ powder-in-tube method. Compared to the undoped tapes, J(c) for all the C-doped samples was enhanced by more than an order of magnitude in magnetic fields above 9 T. At 4.2 K, the transport J(c) for the 5 at. % doped tapes reached 1.85x10(4) A/cm(2) at 10 T and 2.8x10(3) A/cm(2) at 14 T, respectively. Moreover, the critical temperature for the doped tapes decreased slightly. Transmission electron microscopy showed a number of intragranular dislocations and the dispersed nanoparticles embedded within MgB2 grains induced by the C doping. The mechanism for the enhancement of flux pinning is also discussed. These results indicate that powder-in-tube-processed MgB2 tape is very promising for high-field applications.