Magneto-Optical Imaging of Superconducting MgB2 Thin Films
Magneto-Optical Imaging of Superconducting MgB2 Thin Films
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超导 MgB2 薄膜的磁光成像
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
Stephanie Maria Hummed
中科院分区：
文献类型：
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作者：
S. Hummert;Stephanie Maria Hummed
用静态和时间分辨磁光成像方法研究了高温超导体MgB_2在外加磁场和交流电流作用下的变化。平均横截面场和电流分布显示出良好的整体一致性与场相关测量的临界状态模型。偏差可归因于MgB2典型的不规则指状通量渗透。从相位相关的测量得到的屏蔽电流和输运电流的轮廓，这是在定量上与理论相一致。在MgB2薄膜中的磁通前沿的增长已经研究了相对于静态和动态驱动力和分析的定向渗滤脱钉（DPD）模型。静态和动态测量的计算指数与理论一致。数值上的差异突出了驱动力对通量前沿增长的明显影响。基于这些结果，MgB2可以被置于与YBCO和Nb相同的通用性类中。
PAGE The high-temperature superconductor MgB2 has been studied by static and time-resolved magneto-optical imaging a s a function of applied magnetic field and AC current. The averaged cross-sectional field and current profiles show a good overall agreem ent with the critical-state model for the field-dependent m easurem ents. Deviations can be attributed to the irregular finger-like flux penetration typical for MgB2. From the phase dependent m easurem ents both shielding current and transport current profiles are obtained, which are quantitatively in good agreem ent with theory. The flux front growth in the MgB2 thin film has been studied with respect to static and dynamic driving forces and analyzed in terms of the directed percolation depinning (DPD) model. The calculated exponents for static ( ) and dynamic ( ) m easurem ents are in agreem ent with the theory. The difference in the values em phasizes the distinct effect of the driving force on the flux front growth. Based on these results MgB2 can be placed in the sam e universality c la ss a s YBCO and Nb.