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Title: Self-induced steps in a small Josephson junction strongly coupled to a multimode resonator

Journal Article · · Physical Review, B: Condensed Matter; (USA)
 [1];  [2];  [3]
  1. Physikalisch-Technische Bundesanstalt, D-3300 Braunschweig, Federal Republic of Germany (DE)
  2. Danish Institute of Fundamental Metrology, DK-2800 Lyngby, (Denmark)
  3. Physics Laboratory I, B 309, Technical University of Denmark, DK-2800 Lyngby, (Denmark)

An equally spaced series of very large and nearly constant-voltage self-induced singularities has been observed in the dc {ital I}-{ital V} characteristics of a small Josephson tunnel junction strongly coupled to a resonant section of a superconducting transmission line. The system allows extremely high values of the coupling parameter. The current steps are due to subharmonic parametric excitation of the fundamental mode of the resonator loaded by the junction admittance. Using an applied magnetic field to vary the coupling parameter, we traced out half-integer steps as well as the mode steps known from more weakly coupled systems. Based on a single-resonator model, we explain the exceptional size of the steps by the large content of higher harmonics of the Josephson oscillation sustained by the multiple modes of the resonator. The parameters of the junction and the loaded resonator---measured {ital in} {ital situ} by using the junction as detector---form a consistent set. The dominant system loss originates in the junction but cannot be ascribed to a relevant conductance.

OSTI ID:
5679923
Journal Information:
Physical Review, B: Condensed Matter; (USA), Vol. 43:13; ISSN 0163-1829
Country of Publication:
United States
Language:
English