Superconducting properties of saccharin-added bulk MgB2 superconductors

Abstract

In this paper, saccharin was used as the carbon source for addition in bulk MgB2 superconductor. MgB2 samples were successfully prepared with saccharin and ethanol-processed boron using a wet-mixing method. Actual carbon substitution level in the MgB2 lattice increased from 0 to 3.58% with the increasing saccharin content up to 1% and slightly decreased at higher saccharin content. While the 0.1% saccharin-added sample showed the highest critical current density of 2.17 × 105 A/cm2 in the self field at 20 K, the undoped sample showed a lower critical current density of 1.19 × 105 A/cm2. In addition to this, the critical current densities in 4 T field at 10 K for 0.1% and 0.5% saccharin-added samples were calculated to be 1.5 × 104 and 1 × 104 A/cm2, respectively. It was obtained that the addition of low-rate saccharin content did not affect the superconducting transition temperature of the MgB2 sample. These results show that MgB2 fabrication with small amount of saccharin is beneficial to improve critical current density.