2008/09/30 by Shawn Pottorf, Vijay Patel, J. E. Lukens +1
Engineering · Physics and Astronomy · #Advanced Electrical Measurement Techniques #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #cond-mat.supr-con
paper · pdf · doi:10.1063/1.3074446
arxiv created 2008/12/16 · openalex publication_date 2009/01/26 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We measured the low frequency critical current noise in Nb/AlOx/Nb Josephson junctions. Unshunted junctions biased above the gap voltage and resistively shunted junctions biased near the critical current Ic have been measured. For both, the spectral density of δIc/Ic, Sic(f), is proportional to 1/f, scales inversely as the area A and is independent of Jc≡Ic/A over a factor of nearly 20 in Jc. For all devices measured at 4.2 K, Sic(1 Hz)=2.0±0.4×10−12/Hz when scaled to A=1 μm2. We find that, from 4.2 to 0.46 K, Sic(f) decreases linearly with temperature.