Browse Prior Art Database

Reliable Magnetic Bubble Nucleation

IP.com Disclosure Number: IPCOM000076923D
Original Publication Date: 1972-May-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Bogholtz, WE: AUTHOR [+6]

Abstract

In magnetic bubble technology, the problem of reliably nucleating the first "mother" bubble for use in bubble generation is solved by the simple expedient of providing rounded edges on the platelet containing the bubble generator.

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Reliable Magnetic Bubble Nucleation

In magnetic bubble technology, the problem of reliably nucleating the first "mother" bubble for use in bubble generation is solved by the simple expedient of providing rounded edges on the platelet containing the bubble generator.

In the demagnetized state, platelet 1 has many magnetic domain stripes (for example, stripes 2 and 3) each having a width which can be calculated. Bubble generator 4 will always overlie at least one stripe such as stripe 3. There is a tendency that domain stripe 3 will shrink towards the edge of platelet 1 upon the establishment of a magnetic biasing field perpendicular to the plane of the platelet. The undesirable consequence is that the magnetic bubble formed by the shrinking domain will be "hung up" at the edge of the platelet, and be unavailable at the location of the bubble generator 4 where it is needed.

Domain stripe 3 can be pinched off in the presence of the magnetic bias field by etching a trough 5 having rounded shoulders 6 about the perimeter of platelet
1. This assures that domain stripe 3 in the presence of the bias magnetic field shrinks towards bubble generator 4 and not towards the edges of platelet 1, so that the resulting magnetic bubble will be located at the bubble generator. The rounded shoulders 6 are produced inherently by the undercutting action of the etchant underneath the mask used in making trough 5. Alternatively, the edges of platelet 1 can be rounded to produce a simila...