Improved Superconducting Properties in Graphene-Doped MgB₂ Prepared by Coating Method

The effects of graphene doping on the phase formation and superconductivity of MgB₂ bulks synthesized with different process have been studied systemically. Considering the scattering structure of graphene, coating method was applied to enhance the uniformity of graphene doping. The graphene coated B addition was expected to improve the critical current density of MgB₂ bulks. In our study, several experiments were performed to find out the suitable way for graphene doping. The coating method could enhance the critical current density of MgB₂ from 1.9 × 10⁵ to 2.5 × 10⁵ A/cm² at 20 K and 0 T, compared with that of the undoped sample. And the superconductivity of MgB₂ prepared by coating method got obvious improvement at high field compared with that of pure graphene doping bulk. It can be concluded that the coating method could ensure the uniformity of graphene doping in MgB₂ and refined the grain crystalline effectively.