2008/02/11 by S. Sendelbach, David Hover, D. Hover +5
Physics and Astronomy · #Magnetic properties of thin films #Physics of Superconductivity and Magnetism #Theoretical and Computational Physics #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevlett.100.227006
4 pages, 4 figures
arxiv created 2008/02/11 · openalex publication_date 2008/06/05 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We have characterized the temperature dependence of the flux threading dc SQUIDs cooled to millikelvin temperatures. The flux increases as 1/T as temperature is lowered; moreover, the flux change is proportional to the density of trapped vortices. The data are compatible with the thermal polarization of surface spins in the trapped fields of the vortices. In the absence of trapped flux, we observe evidence of spin-glass freezing at low temperature. These results suggest an explanation for the universal 1/f flux noise in SQUIDs and superconducting qubits.