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arXiv 0811.1894cond-mat.supr-con
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高温超导体钻孔内磁场的测量

Measurement of the magnetic field inside the holes of a drilled bulk high-Tc superconductor

Gregory P Lousberg, Jean-Francois Fagnard, Jacques G Noudem, Marcel Ausloos, Benoit Vanderheyden, Philippe Vanderbemden

摘要:

我们使用宏观孔钻在大块的YBCO超导体探测其磁性在样品的体积。样品经受密度范围从30 mT到130 mT的AC磁通量,并且超导体中的磁通量由插入孔中的微型线圈探测。在给定的孔中,可以观察到三种不同的穿透状态:(i)屏蔽状态,其中没有磁通量穿过孔;(ii)逐渐穿透状态,其中磁场的波形具有削波正弦形状,其基波分量与所施加的场成比例;以及(iii)通量集中状态,其中磁场的波形接近正弦波,其振幅超过所施加的场的振幅高达两倍。孔中的渗透制度的分布进行了比较,在样品的顶部和底部表面的磁通量密度,并解释与这些表面的光学偏振光显微照片的帮助。我们表明,孔内的磁场的测量可以被用来作为一个局部表征的样品的体磁性能。

英文摘要:

We use macroscopic holes drilled in a bulk YBCO superconductor to probe its magnetic properties in the volume of the sample. The sample is subjected to an AC magnetic flux with a density ranging from 30mT to 130mT and the flux in the superconductor is probed by miniature coils inserted in the holes. In a given hole, three different penetration regimes can be observed: (i) the shielded regime, where no magnetic flux threads the hole; (ii) the gradual penetration regime, where the waveform of the magnetic field has a clipped sine shape whose fundamental component scales with the applied field; and (iii) the flux concentration regime, where the waveform of the magnetic field is nearly a sine wave, with an amplitude exceeding that of the applied field by up to a factor of two. The distribution of the penetration regimes in the holes is compared with that of the magnetic flux density at the top and bottom surfaces of the sample, and is interpreted with the help of optical polarized light micrographs of these surfaces. We show that the measurement of the magnetic field inside the holes can be used as a local characterization of the bulk magnetic properties of the sample.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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