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Discussing the study on the transport current and its field dependence for the nanometer-size SiC doped MgB2 wires. The results reveal that the nanometer size SiC doped MgB2/Fe wires can carry higher transport I(sub c) and J(sub c) in the magnetic fields ever reported for any form of MgB2.

The nano-SiC doped MgB[sub 2]/Fe wires were fabricated using a powder-in-tube method and an in-situ reaction process. The depression of T[sub 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[sub c](H) performance. The transport J[sub c] for all the wires is comparable to the magnetic J[sub c] at higher fields despite the low density of the samples and percolative nature of current. The transport I[sub c] for the 10wt% SiC doped MgB[sub 2]/Fe reached 660A at 5K and 4.5T (J[sub c] = 133 000A/cm²) and 540A at 20K and 2T (J[sub c] = 108 000A/cm²). The transport J[sub c] for the 10wt% SiC doped MgB[sub 2] wire is more than an order of magnitude higher than for the state-the-art Fe-sheathed MgB[sub 2] wire reported to date at 5K and 10T and 20K and 5T respectively. There is a plenty of room for further improvement in J[sub c] as the density of the current samples is only 50%. [ABSTRACT FROM AUTHOR]