Browse Prior Art Database

Waffle Permalloy Circuit for Bubble Domain Devices

IP.com Disclosure Number: IPCOM000073873D
Original Publication Date: 1971-Feb-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Ahn, KY: AUTHOR [+2]

Abstract

In magnetic bubble domain circuitry, current carrying conductors provide high-speed propagation but have the disadvantage of low density packing. On the other hand, permalloy T-bars and I-bars provide high packing densities but suffer from reduced propagation speed. The device shown above combines permalloy and conductor patterns to produce high-speed propagation and high-density patterns.

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Waffle Permalloy Circuit for Bubble Domain Devices

In magnetic bubble domain circuitry, current carrying conductors provide high-speed propagation but have the disadvantage of low density packing. On the other hand, permalloy T-bars and I-bars provide high packing densities but suffer from reduced propagation speed. The device shown above combines permalloy and conductor patterns to produce high-speed propagation and high- density patterns.

The propagation means comprises conductor loops 1 surrounding permalloy pillars 2 which extend transversely to the plane of the orthoferrite 3 or other medium in which the bubble domains propagate. Domain propagation is achieved by first energizing conductor loops 1, which in turn switch permalloy pillars 2 to attract or repel the bubble domains. The magnetic poles are oriented vertically rather than horizontally to eliminate the disadvantage of T-bar and 1-bar propagation means where the vertical magnetic field is small.

Further, the size of the loop can be smaller than the bubble domain so that the fabrication difficulties of conductor loop propagation means are eliminated.

A method for fabrication of the structure involves etching out a conductor loop 1 after plating or evaporation of metal on magnetic chip 3, followed by a deposition of permalloy pillars 2 through a mechanical mask. For a magnetic chip thickness of 50 microns, the following dimensions are suitable: conductor width: 15 microns

conductor thickness: 1 micron...