Properties of$rm MgB_2$Superconductor by Doping Impurity of SiC, Graphite,$rm C_60$, and C Nano-Tube

Since MgB
₂
superconductor was discovered by Akimitsu, many scientists has been studied this new intermediate temperature superconductor material. Recently Dou reported the critical current density and flux pinning of MgB
₂
is enhanced by doping of SiC nano powder, and Fujii reported MgB
₂
superconductor made by the powder-in-tube in-situ process using MgH
₂
as a precursor powder enhanced the critical current density especially under high magnetic field. Also Matsumoto reported the irreversibility field of MgB
₂
tape prepared by the in-situ powder in tube process using MgH
₂
as a precursor powder increased to 23 T by the SiC doping. These results show MgB
₂
has high potential as a strong candidate for a practical use. We study the effects of doping nano carbon impurity because graphite has the same structure as the hexagonal Boron structure in MgB
₂
. We added carbon impurities of graphite, C
₆₀
, and open-ended carbon nano tube respectively to MgB
₂
conductors made by powder in tube ex-situ process