Substitution-induced pinning in MgB₂superconductor doped with SiC nano-particles

Abstract

By doping MgB_2 superconductor with SiC nano-particles, we have successfully\nintroduced pinning sites directly into the crystal lattice of MgB_2 grains\n(intra-grain pinning). It became possible due to the combination of\ncounter-balanced Si and C co-substitution for B, leading to a large number of\nintra-granular dislocations and the dispersed nano-size impurities induced by\nthe substitution. The magnetic field dependence of the critical current density\nwas significantly improved in a wide temperature range, whereas the transition\ntemperature in the sample MgB_2(SiC)_x having x = 0.34, the highest doping\nlevel prepared, dropped only by 2.6 K.\n