Propagation, collisions and reflections of vortices at the boundaries of a Josephson junction array.

Session B11 - HTSC: JOSEPHSON JUNCTION ARRAYS I
mixed session, Monday morning, March 20, 11:00
Room B3, San Jose Convention Center

[B11.05] Propagation, collisions and reflections of vortices at the boundaries of a Josephson junction array.

Jorge V. Jos\'e (Northeastern University, Boston, MA, USA.),J.E. van Himbergen,T.J. Hagenaars,P.H.E. Tiesinga (Instituut voor Theoretische Fysica, Utrecht, The Netherlands)

We study the propagation properties of a single vortex in a square Josephson junction array (JJA) with free boundaries in the direction perpendicular to an applied d.c.-bias. We model the dynamics of the JJA by the RCSJ-equations. For zero Stewart-McCumber parameter \beta_c we find that (A) the vortex always exits the array when it gets to the boundary. For \beta_c>0 and for low currents we find type A behavior while for larger currents (B) the vortex is reflected as an antivortex at one edge and the antivortex as a vortex at the other, leading to a stationary oscillatory state and to a finite time-averaged voltage. For \beta_c\geq 25 we find a reentrant type behavior (i.e. A\to B\to A\to B ) as the current increases. The exiting and the bouncing of a vortex at the edges is qualitatively explained in terms of a macroscopic model of a vortex interacting logarithmically with its image, however, the reentrant behavior is not. The propagation and collisional properties of a vortex-antivortex pair will also be discussed.

Work supported in part by Fundamenteel Onderzoek der Materie (FOM) and by NSF grant DMR-92-11339

Part B of program listing