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arXiv · 1009.2829

Hysteresis in superconducting short weak links and $μ$-SQUIDs

Dibyendu Hazra·Lætitia Pascal·Hervé Courtois·Anjan K. Gupta
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Abstract

Thermal hysteresis in a micron-size Superconducting Quantum Interference Device ($μ$-SQUID), with weak links as Josephson junctions, is an obstacle for improving its performance for magnetometery. Following the "hot-spot" model of Skocpol et al. [J. Appl. Phys. {\bf 45}, 4054 (1974)] and by incorporating the temperature dependence of thermal conductivity of superconductor using 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 $μ$-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 non-hysteretic regimes. We also discuss the effect of the weak link geometry in order to widen the temperature range of hysteresis-free operation.

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Dibyendu Hazra, Lætitia Pascal, Hervé Courtois, Anjan K. Gupta. 2010-09-15. Hysteresis in superconducting short weak links and $μ$-SQUIDs. https://doi.org/10.1103/physrevb.82.184530

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