Enhanced trapped field in MgB2 bulk magnets by tuning grain boundary pinning through milling
Enhanced trapped field in MgB2 bulk magnets by tuning grain boundary pinning through milling
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DOI：
10.1088/0953-2048/28/5/055016
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发表时间：
2015-04
影响因子：
3.6
通讯作者：
Shoichi Sugino;A. Yamamoto;J. Shimoyama;K. Kishio
中科院分区：
文献类型：
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作者：
Shoichi Sugino;A. Yamamoto;J. Shimoyama;K. Kishio
研究了晶粒尺寸、晶格应变和显微结构对球磨MgB 2块材俘获场特性的影响。在面内晶格参数和转变温度和在面内的X-射线衍射峰宽度的增加的减少发生与研磨作为晶粒细化和碳取代的结果。显微组织分析表明，亚微米尺寸的细MgB 2晶粒连接良好，导致晶界密度增加。磁化大块样品的捕获场表现出很大的改善与研磨，并达到3.72 T在5 K，这是最高的MgB 2散装使用无压合成制备。由于Tc降低，过度研磨导致捕获场的退化。晶界密度的增加和电子散射被认为是通过定量和定性地增强晶界磁通钉扎而产生高俘获场的原因。
The effects of the grain size, lattice strain, and microstructure on the trapped field properties of ball-milled MgB2 bulks were studied. A decrease in the in-plane lattice parameters and transition temperature and an increase in the in-plane x-ray diffraction peak widths occurred with milling as a result of grain refinement and carbon substitution. Microstructural analysis revealed that sub-micron-size fine MgB2 grains were well connected, resulting in increased grain boundary density. The trapped field of the magnetized bulk samples exhibited a large improvement with milling and reached 3.72 T at 5 K, which is the highest among MgB2 bulks prepared using pressureless synthesis. Excess milling resulted in degradation of the trapped field because of Tc reduction. The increased grain boundary density and electron scattering are considered to contribute to the high trapped field through quantitatively and qualitatively enhancing the grain boundary flux pinning.