Three-dimensional microstructure and critical current properties of ultrafine grain Ba(Fe,Co)2As2 bulk superconductors
Three-dimensional microstructure and critical current properties of ultrafine grain Ba(Fe,Co)2As2 bulk superconductors
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超细晶Ba(Fe,Co)2As2体超导体的三维微观结构及临界电流性能
DOI：
10.1016/j.jallcom.2022.166358
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发表时间：
2022
影响因子：
6.2
通讯作者：
Konno Toyohiko J.
中科院分区：
文献类型：
--
作者：
Shimada Yusuke;Tokuta Shinnosuke;Yamanaka Akinori;Yamamoto Akiyasu;Konno Toyohiko J.
在铁基超导体中，随机取向的晶界通过本征弱连接和磁通钉扎机制对输运性质有很大的影响。在这里，我们报告的临界电流密度（Jc）和三维微结构的多晶大块Co掺杂的Ba 122（BaFe 1.84Co 0.16As 2）超导体，具有高度致密的晶界（晶粒尺寸小于50 nm），由高能铣削生产。三维电子显微镜显示，二次粒子的异常生长（聚集）和聚集体间的结构显着不同的样品具有较细的晶粒，这可能有额外的限制Jc。这些重要的微观结构特征被量化为两个参数-局部厚度和总孔隙长度-通过重建的三维结构的超导相，使用自适应阈值法。研究结果表明，了解和控制烧结过程中的微观结构形成过程，有助于提高122种超细晶粒多晶材料的Jc性能。
In iron-based superconductors, randomly oriented grain boundaries have a strong influence on the transport properties via intrinsic weak-link and flux pinning mechanisms. Herein we report the critical current density (Jc) and the three-dimensional microstructure of polycrystalline bulk Co-doped Ba122 (BaFe1.84Co0.16As2) superconductors, with highly dense grain boundaries (grain size smaller than 50 nm), produced by high-energy milling. Three-dimensional electron microscopy revealed that the anomalous growth of secondary particles (aggregation) and the inter-aggregation structures were significantly different in the samples with finer grains, which may have extrinsically limitedJc. These important microstructural features were quantified as two parameters—local thickness and total pore length—by reconstructing the three-dimensional structure of the superconducting phase using the adaptive thresholding method. The results obtained in this study suggest that understanding and controlling the microstructural formation process by sintering are instrumental for improving theJcproperties of 122 polycrystalline materials consisting of ultrafine grains.