The effect of facet lines on critical current density and trapped field in bulk RE-Ba-Cu-O single grains
The effect of facet lines on critical current density and trapped field in bulk RE-Ba-Cu-O single grains
复制标题
晶面线对块状 RE-Ba-Cu-O 单晶粒临界电流密度和俘获场的影响
DOI：
10.1088/1361-6668/ac883d
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发表时间：
2022
影响因子：
3.6
通讯作者：
Shi Y
中科院分区：
文献类型：
--
作者：
Shi Y
大块、单颗粒RE-Ba-Cu-O（其中RE=稀土或钇）[（RE）BCO]高温超导体可潜在地用于产生用于磁共振成像（MRI）和核磁共振（NMR）的稳定磁场。然而，在这些应用中，磁场的均匀性至关重要。因此，临界电流密度的空间分布，J c，在散装单颗粒和磁化过程的影响，这是可实现的捕获磁场的均匀性的主要驱动程序，是根本评估这些技术上重要的材料的性能。本文报道了在77 K下，在直径为20 mm的Gd-Ba-Cu-O样品中，系统测量了单个晶粒沿着刻面线和通过籽晶[（110）-F]的垂直截面上20个位置处的Jc-B分布，试图了解和评估Jc沿沿着这一显微结构特征的分布。在[（100）-a]平面内沿沿着a或B方向测量的整个垂直平面内横跨种子的数据的比较表明，对于0.2 T和2.5 T之间的施加场，在77 K下在小平面线处的J c-B高出10%以上。通过测量从4个不同尺寸和形状的GdBCO-Ag单颗粒样品上切下的截面的俘获场大小及其等值线图，研究了小面线的Jc-B关系对单个块体样品中测量的总俘获场的影响。基于本文报道的结果，我们展示了一种通过优化单个GdBCO单颗粒部分组装来实现更均匀陷阱场的方法。
Bulk, single grain RE–Ba–Cu–O (where RE= rare earth or yttrium)[(RE) BCO] high temperature superconductors could potentially be used to generate stable magnetic fields for magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR). In these applications, however, the homogeneity of the magnetic field is of critical importance. As a result, the spatial distribution of critical current density, J c, within the bulk single grain and the effects of the magnetisation process, which are primary drivers of the uniformity of the achievable trapped magnetic field, are fundamental to assessing the performance of these technologically important materials. This paper reports the systematic measurement of the distribution of J c–B at 77 K over a vertical cross-section of a single grain along a facet line and through the seed crystal [(110)-F] at 20 positions within a 20 mm diameter Gd–Ba–Cu–O sample in an attempt to understand and assess the distribution of J c along this microstructural feature. A comparison of the data within the whole vertical plane across the seed measured along the a or b direction within the [(100)-a] plane shows that J c–B at 77 K at the facet line is more than 10% higher for applied fields between 0.2 T and 2.5 T. The effect of the J c–B relationship of the facet line on the overall trapped field measured in an individual bulk sample was investigated by measuring the magnitudes of trapped fields and their contour maps for sections cut from four single grain samples of GdBCO–Ag at different sizes and shapes parallel to the ab-plane from the top to the bottom of the bulk sample. Based on the results reported here, we demonstrate a method to achieve more uniform trapped fields through an optimal arrangement of an assembly of sections of individual GdBCO single grains.