Improved Superconducting Properties of NaCl Doped MgB2
MgB2 superconducting materials have important application potential in the 20K temperature region, which is a significant advantage compared with other low-temperature superconductors (such as Nb-Ti and Nb3Sn). However, there is a big gap between its superconducting current-carrying capacity and Ni-Ti and Nb3Sn, which is due to the weak magnetic flux pinning force and the poor connection between the MgB2 grains. Chemical doping is a simple and effective method to improve the performance of MgB2. This paper studies the effect of NaCl doping on the performance of MgB2. It is found that NaCl doping has a positive effect on improving the interconnection of MgB2 grains and refining MgB2 grains, and is a potentially effective method to improve the superconducting properties of MgB2. In addition, all of the samples in this study showed surface pinning characteristics, but the smaller the MgB2 grain size, the better the match with the surface pinning characteristics described by Kramer's theory.