Publication
Applied Physics Letters
Paper

Low 1/f noise in YBa2Cu3O7 dc SQUIDs on (Y)ZrO2 bicrystal substrates

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Abstract

We report low noise operation of YBa2Cu3O7 SQUIDs superconducting quantum interference devices using Josephson junctions grown on bicrystal substrates of (Y)ZrO2. Energy sensitivities measured at 10 Hz (Sε=4.5×10-29 J/Hz) were to our knowledge lower than previously reported for a YBa2Cu 3O7 SQUID with practical loop size (∼40 μm). The 1/f part of the voltage noise reached a maximum at 85 K where the noise spectrum was essentially white. The 1/f noise increased both at lower temperatures due to increased critical current fluctuations (∼Ibias2.2) and at higher temperatures, where the flux noise from the film produces a peak below Tc(=89 K).

Date

01 Dec 1992

Publication

Applied Physics Letters