The effect of SiC nanoparticle addition on the flux pinning properties of MgB2

The nanoparticle–MgB2 composite superconducting sample, (SiC)4wt.%(MgB2)96wt.% ((SiC)4–MgB2), was prepared, and the effect of nanoparticle additions on the magnetic flux pinning was investigated. The measurement and comparison of isothermal magnetization M(H), for pure-MgB2 powder and sintered pellets of (SiC)4–MgB2 and pure-MgB2 were carried out at temperatures between 5 and 50K in fields up to 8.5T. The magnetic irreversibility ΔM(H) curves of the (SiC)4–MgB2 follow almost identical lines of both pure-MgB2 powder and sintered bulk MgB2 in the region above a specific magnetic field (called a merged field), which gradually decreases as the temperature increases. The (SiC)4–MgB2 composite superconductor has exhibited the flux pinning effect which comes from both the grain boundaries and the point defect weak pinning centers in the region below the merged field line. This is different from the case of pure-MgB2 powder and sintered bulk MgB2 which showed mostly the grain boundaries pinning.