Hysteresis in superconducting short weak links and μ -SQUIDs
Hysteresis in superconducting short weak links and μ -SQUIDs
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超导短弱连接和 μ-SQUID 中的磁滞
DOI：
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发表时间：
2010
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通讯作者：
Anjan K. Gupta
中科院分区：
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作者：
D. Hazra;L. Pascal;H. Courtois;Anjan K. Gupta
由于超导量子干涉仪（$ensuremath{mu}$-SQUID）的弱连接为约瑟夫森结，其热滞效应是提高其磁学性能的一个障碍。根据Skocpol等人[J.Appl.Phys.45，4054（1974）]的“热点”模型，并通过在线性近似下引入超导体热导率的温度依赖性，我们发现在短的超导Nb基弱链和$ensuremath{mu}$-SQUID中再俘获电流的温度依赖性与观察到的结果更好地一致。此外，利用临界电流的温度依赖性，我们发现，超过一定的温度滞后消失。我们分析的电流-电压特性和薄弱环节的温度变化的滞后和非滞后制度。我们还讨论了弱连接几何形状的影响，以扩大无杂原子操作的温度范围。
Thermal hysteresis in a micron-size superconducting quantum interference device ($ensuremath{mu}$-SQUID), with weak links as Josephson junctions, is an obstacle for improving its performance for magnetometry. Following the ``hot-spot' model of Skocpol et al. [J. Appl. Phys. 45, 4054 (1974)] and by incorporating the temperature dependence of the superconductor thermal conductivity under a linear approximation, we find a much better agreement with the observed temperature dependence of the retrapping current in short superconducting Nb-based weak links and $ensuremath{mu}$-SQUIDs. In addition, using the temperature dependence of the critical current, we find that above a certain temperature hysteresis disappears. We analyze the current-voltage characteristics and the weak link temperature variation in both the hysteretic and nonhysteretic regimes. We also discuss the effect of the weak link geometry in order to widen the temperature range of hysteresis-free operation.