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Logic or Memory Elements Based on the Properties of Thin Walled Super-Conducting Rings (or Microcylinders)

IP.com Disclosure Number: IPCOM000045548D
Original Publication Date: 1983-Apr-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

McLachlan, DS: AUTHOR

Abstract

This device, not being based on the properties of a tunnel barrier, may be easier to fabricate in constant manner. In order to achieve the logic or memory functions, the device described in the preceding article will have to be hysteretic. McLachlan' s experiments (Phys. Rev. Lett. 23, 1434 (1969)) showed that as Lambda (the penetration depth) increases with respect to t (the wall thickness), the entry and exit of flux quanta becomes hysteretic, providing a mechanism for the storage of information. Should the above natural hysteresis prove to be unsuitable, an artificial hysteresis can be introduced by an asymmetric current flowing around the loop 20, as shown in the drawing.

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Logic or Memory Elements Based on the Properties of Thin Walled Super- Conducting Rings (or Microcylinders)

This device, not being based on the properties of a tunnel barrier, may be easier to fabricate in constant manner. In order to achieve the logic or memory functions, the device described in the preceding article will have to be hysteretic.

McLachlan' s experiments (Phys. Rev. Lett. 23, 1434 (1969)) showed that as Lambda (the penetration depth) increases with respect to t (the wall thickness), the entry and exit of flux quanta becomes hysteretic, providing a mechanism for the storage of information.

Should the above natural hysteresis prove to be unsuitable, an artificial hysteresis can be introduced by an asymmetric current flowing around the loop 20, as shown in the drawing.

The device consists of a planar ring 20 to which two current leads 21 and 22, are attached. Two further leads 23 and 24 are attached to leads 21 and 22 respectively. Leads 23 and 24 are sensor leads adapted to detect switching of a flux quanta. The detection could also be done inductively. Line 25 is a possible read line for inductive coupling to loop 20.

The reading and writing of information into these devices will be similar to the cryotron. Advantages over the cryotron are that the inductances (and dimensions) are much smaller and this combined with a high resistivity superconductor will lead to faster switching times. Also, as the flux in the device is an integal number of quanta...