Synthesis of carbon-doped MgB2 superconducting nanowires

A systematic study was conducted on the fabrication, structural characterization, and magnetic properties of MgB2 wire-like nanostructures with C doping between 0% and 20%. Based on chemical vapor deposition technique, non/C-doped MgB2 nanowires (NWs) with an average diameter of 60 nm and length up to several micrometers were produced by homemade MgB2 nanotubes, the mixture gases (Ar + CH4 + H2), and Ni catalyst. Electron and X-ray diffraction confirm that the as-synthesized non/C-doped MgB2 NWs are single crystalline with primitive hexagonal lattice structure. DC magnetization measurements indicate a high superconducting transition temperature (39 K) for nondoping MgB2 NWs and that on increasing the carbon content the transition broadens and shifts toward lower temperatures. The technique is an attractive synthetic method since its flexibility allows for optimization of the doping synthesis. In particular, a comprehensive investigation of influence of NW doping on superconductivity is reported for the first time.