柠檬酸掺杂的MgB2超导体钉扎机理的研究

Evidence of δ/ pinning induced by citric acid doping in MgB_2 superconductor

本文研究了柠檬酸掺杂的MgB2超导材料的Jc-B行为及其钉扎机理.在纯MgB2多晶样品中,δTc钉扎起主要作用,而在掺杂的样品中,则是δl钉扎和δTc钉扎共同作用,并且δl钉扎机理占主要作用,其贡献比重随着掺杂量的增加而增加.从Jc-B行为和钉扎行为的分析都可以得到,柠檬酸掺杂量为15%的MgB2超导材料表现出最好的性能.

The critical current density （ Jc） and flux-pinning mechanism of MgB2 doped with citric acid （ C6H8O7 ） from 0 to 30wt% have been investigated in detail by magnetic and resistive measurements. The temperature dependence of critical current density,Jc（T）,at particular field within the single vortex regime was analyzed. δTc pinning mechanism was found to be the only important pinning mechanism in pure MgB2 samples,while δl pinning is dominant with little effect of δTc pinning for citric acid doped samples. It was observed that the contribution of δl pinning enhances with the increasing doping level of critic acid,and it was also found that MgB2 doped with 15wt% critic acid shows the best performance in Jc-B behavior.