Anomalous results observed in magnetization of bulk high temperature superconductors—A windfall for applications
Anomalous results observed in magnetization of bulk high temperature superconductors—A windfall for applications
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在大块高温超导体磁化中观察到的异常结果——应用的意外收获
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
K. Davey
中科院分区：
文献类型：
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作者：
R. Weinstein;D. Parks;R. Sawh;K. Carpenter;K. Davey
最近的脉冲零场冷磁化实验显示了意想不到的结果。例如，观察到可再现的、非破坏性的、快速的、巨大的场跳跃（GFL）到更高的穿透场。观察结果与临界状态模型（CSM）在几个方面不一致。为了澄清观测到的异常现象所涉及的物理现象，还进行了其他实验。在这里，我们提出的Jc依赖的异常功能的实验结果。结果表明，GFL中的电场突然增加是Jc的单调增加函数。获得最大可捕获场BT，max所需的脉冲场幅度BA，max的比值（CSM预测为≥2.0）在高Jc时逐渐接近1.0。测试使用的脉冲值，施加场BA，最大值略低于GFL表现出两个额外的异常：（i）在高Jc，最高的捕获场是高达106倍低于CSM预测，（ii）测量的洛伦兹力作为Jc的函数偏离CSM预测急剧。这些数据排除了热效应和钉扎中心几何形状作为这些异常的可能物理原因。推测原因被认为是。
Recent experiments on pulsed-zero field cool magnetization of bulk high JcYBCO (YBa2Cu3O7-δ) have shown unexpected results. For example, reproducible, non-destructive, rapid, giant field leaps (GFLs) to higher penetrated field are observed. The observations are inconsistent with the critical state model (CSM), in several aspects. Additional experiments have been pursued in an attempt to clarify the physics involved in the observed anomalies. Here, we present experimental results for the Jc dependence of the anomalous features. It is found that the sudden field increase in the GFL is a monotonically increasing function of Jc. The ratio of required pulsed field amplitude, BA,max, to obtain maximum trappable field, BT,max, which CSM predicts to be ≥2.0, gradually approaches 1.0 at high Jc. Tests using values of pulsed, applied field BA,max just below the GFL exhibit two additional anomalies: (i) At high Jc, the highest trapped field is up to ∼6 times lower than predicted by CSM, and (ii) the measured Lorentz force as a function of Jc deviates sharply from CSM predictions. The data rule out heating effects and pinning center geometry as possible physical causes of these anomalies. A speculative cause is considered.
影响因子：
3.6
作者：
Durrell, J. H.;Dennis, A. R.;Cardwell, D. A.
通讯作者：
Cardwell, D. A.