Regensburg 2007 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 8: Superconductivity - Poster Session

TT 8.34: Poster

Monday, March 26, 2007, 14:00–17:45, Poster A

Thermal activation and phase diffusion in long submicron annular junctions — •Astria N. Price¹, Alexander Kemp¹, William D. Oliver², and Alexey V. Ustinov¹ — ¹Physikalisches Institut III, Universität Erlangen-Nürnberg, Erwin-Rommel-Str 1, 91058 Erlangen, Germany — ²MIT Lincoln Laboratory, 244 Wood Street, Lexington, Massachusetts 02420, USA

We report measurements of the standard deviation of the switching current from the flux-free state in long annular Josephson junctions of differing submicron width, over the temperature range T ~ 25 - 750 mK. A power law dependence is observed between 200 and 500 mK, while at lower temperatures the standard deviation saturates due to phase escape via quantum tunneling. As the temperature increases above T ~ 500 mK the standard deviation decreases, which we interpret as an observation of phase diffusion in an extended Josephson system.