• DOI:10.1063/1.4739850
• Corpus ID: 55428174

Direct current superconducting quantum interferometers with asymmetric shunt resistors

@article{Rudolph2012DirectCS,
  title={Direct current superconducting quantum interferometers with asymmetric shunt resistors},
  author={Matthias Rudolph and Joachim Nagel and Johannes Maximilian Meckbach and Matthias Kemmler and M. Siegel and Konstantin Ilin and Dieter Koelle and Reinhold Kleiner},
  journal={Applied Physics Letters},
  year={2012},
  volume={101},
  pages={052602}
}

• M. Rudolph, J. Nagel, +5 authors R. Kleiner
• Published 30 June 2012
• Physics
• Applied Physics Letters

We have investigated asymmetrically shunted Nb/Al-AlOx/Nb direct current (dc) superconducting quantum interference devices (SQUIDs). While keeping the total resistance R identical to a comparable symmetric SQUID with R−1=R1−1+R2−1, we shunted only one of the two Josephson junctions with R=R1,2/2. Simulations predict that the optimum energy resolution ϵ and thus also the noise performance of such an asymmetric SQUID can be 3–4 times better than that of its symmetric counterpart. Experiments at a temperature of 4.2 K yielded ϵ≈32 ℏ for an asymmetric SQUID with an inductance of 22 pH. For a comparable symmetric device, ϵ=110 ℏ was achieved, confirming our simulation results.