TiC和SiC掺杂MgB2超导体的对比研究

Comparision of the superconducting properties in both TiC and SiC doped MgB2 bulks

分别制备了8％（质量分数）的TiC和5％（质量分数）的SiC掺杂的MgB2超导块材，并对比分析了这两种掺杂物对MgB2超导块材的性能影响。所有样品均在流动的Ar气保护下在不同退火温度下退火，研究发现TiC掺杂和SiC掺杂的MgB2样品的最优化工艺参数分别是900℃保温1h和720℃保温1h。随后采用XRD和SEM分别对样品进行了相成份和微观结构的分析，并采用PPMS测试了样品的磁滞回线并由Bean模型计算出了样品的临界电流密度。在4．2K，0T下TiC掺杂的五值为1．0×10^5A／cm^2，而10K，0T下SiC掺杂样品的五值为4×100A／cm^2。而且随着外加磁场的增加，SiC掺杂MgB2样品的五值下降得比TiC掺杂的MgB2样品要缓慢很多，这表明了SiC掺杂比TiC掺杂更有利于改善MgB2在高场下的超导电性能。

8wt% TiC doped and 5wt% SiC doped MgB2 bulks were in-situ synthesized and the samples were sintered at various temperatures under the At atmosphere protection. The optimized sintering parameter for TiC doped MgB2 sample was found to be 900℃ for lh, and SiC doped one was 720℃ for lh. The samples were analysised by the XRD, SEM and the magnetic Jc measurements. It was found that the Jc values of TiC doped samples were reached to 1.0 ～ 105A/cm^2 at 4.2K in self field and SiC doped samples were reached to 4.0 ～ 105A/cm^2 at 10K in the self field. Meanwhile, with the increase of the magnetic field, the Jc value in SiC doped MgB2 sample was decreased slowly when comapred to that of TiC doped one, indicating that the SiC doping is more effective for the improvement of the critical current density in MgB2 at higher magnetic field than that of the TiC doping.