Microscopic Analysis of Low-Frequency Flux Noise in YBa${}_2$Cu${}_3$O${}_7$ Direct Current Superconducting Quantum Interference Devices

Abstract

We use low-temperature scanning electron microscopy combined with SQUID detection of magnetic flux to image vortices and to investigate low-frequency flux noise in YBa${}_2$Cu${}_3$O${}_7$ thin film SQUIDs. The low-frequency flux noise shows a nonlinear increase with magnetic cooling field up to 60 $\mu$T. This effect is explained by the surface potential barrier at the SQUID hole. By correlating flux noise data with the spatial distribution of vortices, we obtain information on spatial fluctuations of vortices on a microscopic scale, e.g. an average vortex hopping length of approximately 10 nm.

arXiv commentsubmitted to Applied Physics Letters

References in corpus (2)

• The Flux-Line Lattice in Superconductors
• Low-frequency flux noise and visualization of vortices in a YBa2Cu3O7 dc SQUID washer with an integrated input coil

Cited by in corpus (5)

• Response of thin-film SQUIDs to applied fields and vortex fields: Linear SQUIDs
• Sheet-current distribution in a dc SQUID washer probed by vortices
• Imaging of Thermal Domains in ultrathin NbN films for Hot Electron Bolometers
• Flux noise in ion-implanted nanoSQUIDs
• Electron-beam-induced shift in the apparent position of a pinned vortex in a thin superconducting film