MIDIT OFD CATS Modelling, Nonlinear Dynamics Optics and Fluid Dynamics Chaos and Turbulence Studies and Irreversible Thermodynamics Risø National Laboratory Niels Bohr Institute and Technical University of Denmark Building 128 Department of Chemistry Building 321 P.O. Box 49 University of Copenhagen DK-2800 Lyngby DK-4000 Roskilde DK-2100 Copenhagen Ø Denmark Denmark Denmark
by Abdelhadi Benabdallah
Laboratoire de Mathematiques,
INSA de Rouen
Mont Saint Aignan, France
Friday June 4, 1999, 15.15 h
at MIDIT, IMM Building 305, room 027
Modern Josephson junctions due to their process of
fabrication are surrounded by a passive (linear)
region where the thickness of the oxide layer prevents
the passage of the supercurrent. This protects the
oxide layer from degradations due to the environment
and provides an electromagnetic cavity to enhance the
power of the device.
We present a numerical and analytic study of the influence
of the passive region on fluxon dynamics where we examine
the effect of the extension of the passive region and its
electromagnetic characteristics, its surface inductance
L I and capacitance CI.
When the velocity in the passive region vs is equal to the Swihart velocity (1) a one dimensional model describes well the operation of the device. When vs is different from 1, the fluxon adapts its velocity to vs. In both cases we give simple formulas for the position of the limiting voltage of the zero field steps. Large values of LI and CI lead to different types of solutions which are analysed.