Graduate School in Nonlinear Science

Sponsored by the Danish Research Academy

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

MIDIT-seminar 453

Friday June 4, 1999, 15.15 h
at MIDIT, IMM Building 305, room 027

Abstract: 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.