Effects of TiB2 doping on the critical current density of MgB2 wires

TiB2 doped MgB2 wires, with the component of Mg:B:TiB2 = 1:2:x (x = 0%, 5%, 8% and 10%), were fabricated through the in situ powder-in-tube method. Samples were sintered at 750 °C for 1 h in a flow of high purity argon. At 4.2 K, the 8 mol% TiB2 doped wire shows the highest critical current density (Jc) in magnetic fields lower than 2.5 T, but the 5 mol% TiB2 doped sample exhibits the highest Jc values at fields above 2.5 T. The magnetic field dependence of Jc for the 5 mol% TiB2 doped wire is slightly weakened in the whole fields. The improved grain connection as well as the decreased MgB2 grain size, which is caused by TiB2 doping, is responsible for the enhancement of Jc for the doped MgB2 wire.