Field trapping property of HTS bulk magnet with reduced voids in pulsed field magnetizing process
Field trapping property of HTS bulk magnet with reduced voids in pulsed field magnetizing process
复制标题
脉冲场磁化过程中空洞减少的高温超导块体磁体的场俘获特性
DOI：
10.1088/1742-6596/400/2/022089
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
A. Murakami
中科院分区：
文献类型：
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作者：
T. Oka;H. Seki;D. Ishiduka;J. Ogawa;S. Fukui;T. Sato;K. Yokoyama;A. Murakami
熔融织构块材超导体在激活过程中会产生数T的强磁场，在样品中产生磁应力，这使得材料的场俘获能力受到力学性能的限制。因此，采用增强技术来提高材料的韧性是非常重要的。在本实验中，我们采用了一种致密的Dy基高温超导块材，通过控制热处理过程中内部空洞的浓度来制备。利用GM制冷机，在30.6K以下的温度范围内施加了7.66T的单脉冲磁场，并讨论了脉冲磁场的分布和由此产生的俘获场的性能。结果表明，随着脉冲场上升时间的延长和初始温度的降低，俘获场增大。致密制造的Dy 123样品在31 K下以相同的方式被激活至1.98 T，当施加7.66 T的磁脉冲场时，与多孔Gd 123样品没有实质性差异。与Gd_（123）化合物相比，Dy_（123）化合物在40K时，在4.64T下的温升超过30K，但在20K以下的温升并不明显。这是由于致密Dy_（123）化合物的Jc值低于Gd_（123）化合物，反映了Gd_（123）化合物的场俘获能力。
The field trapping ability of melt-textured bulk superconductors is usually restricted by the mechanical properties because of the magnetic stress induced in the samples during the activation processes which give them intense magnetic fields of several T Therefore it is of crucial importance to enhance the toughness of the materials by means of reinforcing techniques. In this experiment, we adopted a dense Dy-based HTS bulk sample fabricated by means of controlling the concentration of voids inside during the heat treatment. A single magnetic pulse fields up to 7.66 T have been applied in the temperature range down to 30.6 K with use of GM refrigerator and the profiles of pulsed fields and the resultant trapped fields are discussed with respect to their performances. It was found that the trapped field grows as elongating rise time of the pulsed field and lowering initial temperature. The densely fabricated Dy123 sample was activated up to 1.98 T at 31 K in the same manner with no substantial difference from the porous Gd123 samples when the magnetic pulse field of 7.66 T was applied. The temperature rises up to 20 K are not substancial in comparison to those of the Gd123 compounds which exhibit the temperature rises more than 30 K at 40 K by applying 4.64 T This is attributed to the fact that the Jc value of the dense Dy123 are inferior to that of Gd123, which reflectes the field trapping ability.