Research Progress in Effect of Doping and Irradiation on Superconductivity of MgB_2

The recent research progress in effects of doping and irradiation on the superconductivity of MgB_2 is reviewed and discussed in this paper.Although there are a very few impurities that can enhance the critical temperature of MgB_2 by doping,it is clarified that most of the impurity doping increases obviously the critical current density and the irreversible field of MgB_2.So far nano-SiC is considered as the most effective material that improves the supereon- ducting characteristics of MgB_2 by doping.On the other hand,it is found that a proper dose of irradiation can also im- prove largely the electro-magnetic characteristics of MgB_2 samples.