English

Hysteresis in superconducting short weak links and $\mu$-SQUIDs

Superconductivity 2015-05-19 v1

Abstract

Thermal hysteresis in a micron-size Superconducting Quantum Interference Device (μ\mu-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\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 non-hysteretic regimes. We also discuss the effect of the weak link geometry in order to widen the temperature range of hysteresis-free operation.

Keywords

Cite

@article{arxiv.1009.2829,
  title  = {Hysteresis in superconducting short weak links and $\mu$-SQUIDs},
  author = {Dibyendu Hazra and Lætitia Pascal and Hervé Courtois and Anjan K. Gupta},
  journal= {arXiv preprint arXiv:1009.2829},
  year   = {2015}
}

Comments

11 pages, 12 figures