本文通过磁性测量获得了葡萄糖掺杂MgB2块材样品的临界电流密度Jc，并利用集体钉扎模型分析了掺杂对其磁通钉扎机制的影响．研究发现，在纯样中δTc钉扎为主导钉扎机制；而在掺杂样品中，随着掺杂量的增加础钉扎所占比重逐渐增大到90％．剩余电阻率的计算结果也验证了掺杂样品中的钉扎机制变化．我们推断础钉扎主要是由碳对硼位掺杂引起的晶格无序造成的．
In this paper, the critical current density Jc of pure and glucose-doped MgB2 bulk samples have been obtained by magnetic measurement. The effects of doping on the flux pinning mechanism have been analyzed according to the collective pinning model. It is found that the δTc pinning mechanism is mainly responsible for pure MgB2 sample while the δl pinning mechanism becomes dominant for glucose-doped samples. Further investigation revealed that in doping samples the δTc pinning also appeared, but with the increasing doping level the proportion of δTc pinning decreased, while the δl pinning gradually increased to 90%. The corrected residual rdsistivity results confirm the change of pinning mechanism in doped samples. It is demonstrated that the δl pinning is mainly caused by the lattice disorder effect arising from the substitution effects of carbon.
参考文献
| [1] | W K Yeoh;J H Kim;J Horvat .Control of nano carbon substitution for enhancing the critical current density in MgB_2[J].Superconductor Science & Technology,2006(6):596-599. |
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