Synthesis of superconductor MgCNi3 with carbon nanotubes

MgCNi₃, an intermetallic compound superconductor with a cubic perovskite crystal structure, has been synthesized using fine Mg and Ni powders and carbon nanotubes (CNTs) as starting materials by the conventional powder metallurgy method. The composition, microstructure and superconductivity are characterized using x-ray diffraction (XRD), energy dispersive x-ray (EDX) analysis, scanning electron microscopy (SEM), and superconducting quantum interference device (SQUID) magnetometer. The results indicate that the phases of the synthesized samples are MgCNi₃ (major phase) and traces of C and MgO. The MgCNi₃ particle sizes range from several hundreds of nanometres to several micrometres. The onset superconducting transition temperature T_c of the MgCNi₃ sample is about 7.2\,K. The critical current density J_c is about 3.44×10⁴A/cm² calculated according to the Bean model from the magnetization hysteresis loop of the slab MgCNi₃ sample at 5K and zero applied field.