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Levitation force of Graphene added bulk MgB2 superconductor
Cryogenics ( IF 2.1 ) Pub Date : 2021-07-20 , DOI: 10.1016/j.cryogenics.2021.103343
D. Tripathi 1 , Ashish Bhatnagar 1 , Shalini Raj 2 , D.K. Rai 1 , T.K. Dey 2
Affiliation  

The effect of Graphene addition on levitation/suspension force of bulk MgB2 superconductor has been studied in both zero field cooling (ZFC) and field cooling (FC) conditions at different temperatures. For this, the pristine, 0.5, 1 and 3 wt% of Graphene added bulk MgB2 samples are prepared by solid state reaction method under argon atmosphere. X-Ray diffraction (XRD) and scanning electron microscopy (SEM) of prepared samples have been performed for structural characterization and surface morphology respectively. The structural characterization shows well developed phase of MgB2 while hexagonal shaped grains are evident in SEM photographs. Electrical resistivity measured between 20 K and 300 K confirms a decrease in superconducting transition temperature (TC) and increase in normal state resistivity of pristine MgB2 due to Graphene addition. The levitation force measurement under zero field cooling condition reveals that low level (0.5 wt%) of Graphene addition enhances the levitation force throughout the investigated temperature range. However the levitation force measurements performed at different initial field height under field cooling condition confirm the presence of both attractive and repulsive force. Further, the maximum levitation force (FMLF) and maximum attractive force (FMAF) estimated from the field cooling data of pure and Graphene added MgB2 is found to be a strong function of initial field cooling height (HFC). The maximum repulsive/levitation force (FMLF) increases exponentially with increase in initial field cooling height, while an exponential decrease in attractive force (FMAF) of MgB2 has been observed with increase in initial field cooling height.



中文翻译:

石墨烯添加块状MgB2超导体的悬浮力

已经在零场冷却 (ZFC) 和场冷却 (FC) 条件下在不同温度下研究了添加石墨烯对块体 MgB 2超导体的悬浮/悬浮力的影响。为此,在氩气氛下通过固态反应方法制备了原始的、0.5、1 和 3 重量%的石墨烯添加块状 MgB 2样品。已对制备的样品进行 X 射线衍射 (XRD) 和扫描电子显微镜 (SEM),分别用于结构表征和表面形貌。结构表征显示 MgB 2相发育良好,而六边形晶粒在 SEM 照片中很明显。在 20 K 和 300 K 之间测量的电阻率证实了超导转变温度 (TC ) 和由于石墨烯的添加导致原始 MgB 2 的常态电阻率增加。零场冷却条件下的悬浮力测量表明,在整个研究温度范围内,低水平(0.5 wt%)的石墨烯添加量增强了悬浮力。然而,在场冷却条件下在不同初始场高度下进行的悬浮力测量证实了吸引力和排斥力的存在。此外,最大悬浮力(F MLF)和最大吸引力(F MAF)从场冷却的纯石墨烯和加入的MgB数据估计2被发现为初始场冷却高度的强函数(H FC)。最大排斥/悬浮力(F MLF)随着初始场冷却高度的增加呈指数增加,而观察到MgB 2 的吸引力(F MAF)随着初始场冷却高度的增加呈指数下降。

更新日期:2021-07-28
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