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Bubble Device Fabrication

IP.com Disclosure Number: IPCOM000085748D
Original Publication Date: 1976-May-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Ahn, KY: AUTHOR

Abstract

Bubble domain chips using amorphous magnetic films, and bubble domain chips using electron-beam resist often have to be processed at low temperatures, where the process temperatures are limited to about 100-150 degrees C. However, when magnetic layers such as NiFe are deposited at these low temperatures, various problems develop. For instance, the adhesion of the NiFe films is usually poor and their coercivity is generally high. Perpendicular anisotropy dominates the magnetization and the coercivity is usually in the range of 25-50 Oe. Also, the magnetoresistive effects in the NiFe films are generally lower than those which are prepared at higher substrate temperatures.

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Bubble Device Fabrication

Bubble domain chips using amorphous magnetic films, and bubble domain chips using electron-beam resist often have to be processed at low temperatures, where the process temperatures are limited to about 100-150 degrees C. However, when magnetic layers such as NiFe are deposited at these low temperatures, various problems develop. For instance, the adhesion of the NiFe films is usually poor and their coercivity is generally high. Perpendicular anisotropy dominates the magnetization and the coercivity is usually in the range of 25-50 Oe. Also, the magnetoresistive effects in the NiFe films are generally lower than those which are prepared at higher substrate temperatures.

In order to be able to fabricate bubble domain chips at low-process temperatures, it is proposed to use a nonmagnetic adhesive film, such as Cr, Ti, etc., between the dielectric spacer on the bubble domain material and the NiFe layer. Additionally, the sensor area of the bubble chip is comprised of laminations of NiFe and the adhesive film material.

When the sensor is laminated, the coercivity H(c) decreases and the magnetoresistive effects increase. This technique can be extended to thicker NiFe films by simply repeating the lamination process. For instance, three layers of NiFe, each of which is 1000 angstroms thick, can be laminated by two Cr films, each of which is about 70 angstroms thick. An increase in magnetoresistive effect by 100% can be readily obtained.

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