Transport critical current density in Fe-sheathed nano-SiC doped MgB2 wires

The nano-SiC doped MgB₂/Fe wires were fabricated using a powder-in-tube method and an in-situ reaction process. The depression of T_c with increasing SiC doping level remained rather small due to the counterbalanced effect of Si and C co-doping. The high level SiC co-doping allowed creation of the intra-grain defects and nano-inclusions, which act as effective pinning centers, resulting in a substantial enhancement in the J_c(H) performance. The transport J_c for all the wires is comparable to the magnetic J_c at higher fields despite the low density of the samples and percolative nature of current. The transport I_c for the 10wt% SiC doped MgB₂/Fe reached 660A at 5K and 4.5T (J_c=133000A/cm²) and 540A at 20K and 2T (J_c=108000A/cm²). The transport J_c for the 10wt% SiC doped MgB₂ wire is more than an order of magnitude higher than for the state-the-art Fe-sheathed MgB₂ wire reported to date at 5K and 10T and 20K and 5T respectively. There is a plenty of room for further improvement in J_c as the density of the current samples is only 50%.