Hybrid microwave synthesis of MgCNi₃ superconductor

The superconductor MgCNi3, an intermetallic compound with a cubic perovskite crystal structure, was synthesized from Mg, Ni and graphite powders by hybrid microwave heating in a short time. The phases, microstructures and superconductivity were characterized using x-ray diffraction, energy dispersive x-ray analysis, scanning electron microscopy, the standard four-probe method and magnetic measurements. The results indicate that the phases of the synthesized sample are MgCNi3 (major phase), a small amount of unreacted graphite and a little MgO. The MgCNi3 particle sizes range from two to several microns. The onset superconducting transition temperature of the MgCNi3 sample was 6.9 K, and the superconducting transition width was about 0.8 K.