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Browse Prior Art Database

Bubble Domain Devices in Magnetic Sheets of Variable Thickness

IP.com Disclosure Number: IPCOM000075779D
Original Publication Date: 1971-Nov-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Romankiw, LT: AUTHOR

Abstract

Localized thickness variations in magnetic sheets in which cylindrical magnetic domains (bubble domains) can be propagated are useful for device application. For instance, bubble bursters, amplifiers, and guides can be provided.

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Bubble Domain Devices in Magnetic Sheets of Variable Thickness

Localized thickness variations in magnetic sheets in which cylindrical magnetic domains (bubble domains) can be propagated are useful for device application. For instance, bubble bursters, amplifiers, and guides can be provided.

In Fig. 1, a bubble burster is shown in which a magnetic sheet 10 has a locally thin region 12. Thin region 12 is fabricated by chemical etching. sputter etching, mechanical etching, ultrasonic etching, etc. Domains 14 are propagated to the thin region 12 by conventional propagation means, such as permalloy overlay 16. Domains 14 collapse in region 12, since the thickness of region 12 is less than the critical thickness required for domain stability at a given bias field.

Fig. 2 shows a domain amplifier having a locally thick region 18 in the magnetic sheet 10. Region 18 is produced by epitaxial growth, evaporation, sputtering, or by etching and polishing starting with a thick sheet. Domains 14 are brought to region 18 by permalloy overlay 16. Upon entering region 18, the cylindrical domains expand.

Fig. 3 shows the use of grooves 20 in magnetic sheet 10. Grooves 20 provide forbidden regions for the domains. These grooves prevent the domain from accidentally entering the wrong parts of sheet 10 and thereby act as guides. Domains 14 follow propagation pattern 16.

Fig. 4 shows a top view of a 90 degrees turn, using grooves 20 as guides in conjunction with permalloy bars 16. Doma...