Effects of TiC doping on the upper critical field of MgB2 superconductors

TiC doped MgB2 bulks were fabricated by two-step reaction method. The sample with a nominal compositions of Mg(B0.95(TiC)0.05)4 was first sintered at 1000 °C for 0.5 h. An appropriate amount of Mg was added to reach the stoichiometry of Mg(B0.95(TiC)0.05)2, which was sintered at 750 °C for 2 h.The Hc2 for the micro-TiC doped MgB2 reached 12 T at 20 K. And Jc is 5.3 × 104 A/cm2 at 20 K and 1 T. The results indicate that the two-step reaction method could effectively introduce the carbon in TiC into the MgB2 crystalline lattice, and therefore improve the upper critical field.