Stray magnetic coupling between neighboring superconducting memory cells in dense arrays of Josephson interferometers

Experimental measurements of the coupling between neighboring single-flux-quantum cells are compared with numerical calculations made using a two-dimensional model of the structure. Good agreement is found both for the influence of a control current in one cell on the neighboring cells, and for the effect of the stray field due to a stored flux quantum. The magnitudes of these unwanted effects between memory cells having the bridge-type interferometer structure are calculated as the minimum linewidth is reduced, and the limits to miniaturization imposed by stray magnetic coupling are estimated.