Critical-state model for harmonic generation in high-temperature superconductors.
Critical-state model for harmonic generation in high-temperature superconductors.
复制标题
高温超导体中谐波产生的临界状态模型。
DOI：
10.1103/physrevb.40.10936
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
M. Tinkham
中科院分区：
文献类型：
--
作者：
L. Ji;R. H. Sohn;Gabriel C. Spalding;Christopher Lobb;M. Tinkham
高温超导体在交流磁场中会产生谐波。为了解释这一现象，我们提出了一个宏观的临界状态模型作为替代的Jeffries等人所使用的环路模型。而原来的Bean模型的临界状态只预测奇次谐波，我们的扩展模型还预测偶次谐波考虑到依赖的临界电流磁场。谐波信号作为交流磁场、直流磁场、温度和谐波数的函数的测量结果与所提出的模型一致。特别是，我们发现，随着磁场的增加，临界电流从Bean区（其中${J}_{c}$与磁场无关）过渡到Anderson-Kim区（其中${J}_{c}$与磁场近似成反比）。
High-temperature superconductors exhibit harmonic generation when immersed in an ac magnetic field. To explain this phenomenon, we propose a macroscopic critical-state model as an alternative to the loop model used by Jeffries et al. While the original Bean model of the critical state only predicts odd harmonics, our extended model also predicts even harmonics by taking into account the dependence of the critical current upon magnetic field. The results of our measurements of harmonic signals as a function of ac magnetic field, dc magnetic field, temperature, and harmonic number are consistent with the proposed model. In particular, we find that, as the magnetic field is increased, the critical current crosses over from the Bean regime, where ${J}_{c}$ is independent of field, to the Anderson-Kim regime, where ${J}_{c}$ is approximately inversely proportional to the field.