Dresden 2003 – wissenschaftliches Programm

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DY: Dynamik und Statistische Physik

DY 46: Poster

DY 46.105: Poster

Donnerstag, 27. März 2003, 15:30–18:00, P1

Observation of breather-like states and resonances in a single Josephson cell — •F. Pignatelli and A. V. Ustinov — Physikalisches Institut III, Universität Erlangen-Nürnberg, Erwin-Rommel-str. 1, D-91058 Erlangen.

The study of broken-symmetry states (breather-like) in small structures as single Josephson cells has been proposed to get an insight in localized states of more complex systems as ladders and two dimensional Josephson junction arrays. We present a study of these states in a single cell composed by a superconducting loop with three small underdamped Nb/Al-AlO_x/Nb Josephson junctions. In order to vary the parameter of the system, the measurements are performed in a wide temperature range between 4 K and 8 K. The measured dependence of the region of existence and stability of the breather-like states on the damping is found to be in good agreement with the theoretical expectations. The current-voltage characteristics of the broken-symmetry state show resonances due to interaction between the breather and the electromagnetic oscillations of the cell. The experimental dependence of the magnitude of these resonances on the external magnetic field is consistent with theory.