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Self Resetting Josephson Junction

IP.com Disclosure Number: IPCOM000080849D
Original Publication Date: 1974-Feb-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Jutzi, WW: AUTHOR

Abstract

Resonance effects occurring in Josephson junctions can be used to make a cross-control line gate of special geometry self-resetting. The junction length is chosen for a lambda/2 resonance voltage near the operating point in the voltage state and below the minimum Josephson current at zero control field. For a particularly good voltage swing limitation the operating point is chosen in the steep part of the two-particle current jump, e.g., by half the gap voltage, slightly below the resonance line. After the control signal ceases, the gate resets automatically to the superconducting state.

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Self Resetting Josephson Junction

Resonance effects occurring in Josephson junctions can be used to make a cross-control line gate of special geometry self-resetting. The junction length is chosen for a lambda/2 resonance voltage near the operating point in the voltage state and below the minimum Josephson current at zero control field. For a particularly good voltage swing limitation the operating point is chosen in the steep part of the two-particle current jump, e.g., by half the gap voltage, slightly below the resonance line. After the control signal ceases, the gate resets automatically to the superconducting state.

Resonance effects depend on the magnetic self-field of the junction and the external field applied by control currents I(c). The voltages of resonance lines are given by the junction length L. The ratio L over Josephson penetration depth lambda j is larger than two. The junction width w parallel to the gate current I(g) is chosen smaller than - or equal to - the Josephson penetration depth. These design criteria lead to the hammer-like shape of the cross-line junction, as sketched in Fig. A. The junction is on top of a superconducting ground plate.

Below a certain threshold the control and self-field in one junction half add and subtract in the other half, so that the decrease of the maximum Josephson current in the one half is compensated by the increase in the other half. The control characteristic (Fig. B) shows a nearly constant maximum Josep...