Investigation of lauric acid dopant as a novel carbon source in MgB2 wire

Abstract We fabricated lauric acid (LA) doped MgB 2 wires and investigated the effects of the LA doping. For the fabrication of the LA-doped MgB 2 wires, B powder was mixed with LA at 0–5 wt.% of the total amount of MgB 2 using an organic solvent, dried, and then the LA-treated B and Mg powders were mixed stoichiometrically. The powder mixture was loaded into an Fe tube and the assemblage was drawn and sintered at 900 °C for 3 h under an argon atmosphere. We observed that the LA doping induced the substitution of C for the B sites in MgB 2 and that the actual content of C increased monotonically with increasing LA doping level. The LA-doped MgB 2 wires exhibited a lower critical temperature ( T c ), but better critical current density ( J c ) behavior in a high magnetic field: the 5 wt.% LA-doped sample had a J c value of 5.32 × 10 3  A/cm 2 , which was 2.17 times higher than that of the pristine sample (2.45 × 10 3  A/cm 2 ) at 5 K and 6 T, suggesting that LA is an effective C dopant in MgB 2 for enhancing the high-field J c performance.