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Amorphous Magnetic Bubble Domain Materials with Compositional Gradients

IP.com Disclosure Number: IPCOM000082399D
Original Publication Date: 1974-Nov-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 3 page(s) / 21K

Publishing Venue

IBM

Related People

Cuomo, JJ: AUTHOR [+2]

Abstract

Amorphous magnetic bubble domain materials can be made having lateral compositional gradients, by varying one or more of the components of a multicomponent system. The chemical gradient so produced can be steep or gradual, in accordance with the desired use of such a gradient.

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Amorphous Magnetic Bubble Domain Materials with Compositional Gradients

Amorphous magnetic bubble domain materials can be made having lateral compositional gradients, by varying one or more of the components of a multicomponent system. The chemical gradient so produced can be steep or gradual, in accordance with the desired use of such a gradient.

To fabricate amorphous bubble films having uniform chemical gradients, advantage is taken of the preferential resputtering of species in a multicomponent system and the use of bias sputtering in a rotating system. Under certain conditions a chemical gradient can be produced. For example, a radial increase in Gd concentration across a film of Gd-Co can be obtained by using various combinations of bias voltage, target compositional separations, target to substrate distance, and target starting composition.

To obtain a sharp chemical gradient, targets with radial compositional variations are used. The magnitude of the gradient in the film composition can be varied by bias adjustments. Bands of different compositions can also be fabricated in a target, in order to produce these effects in the amorphous bubble film.

Since film magnetization is approximately directly proportional to composition and since the strip width is proportional to 1/M(s)/2/, the variation in film composition across a bubble film can be detected by the variation in domain strip width across the film surface. The strip width W(s) of a magnetic film is more sensitive to local chemical change than the usual chemical detection methods. When all other considerations are held constant, such as film thickness h and anisotropy K(u), and for a limited range of compositions, the following relationships hold:

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These lateral chemical gradients can be used for enhancement of various device functions. For example, bubble domain propagation can be accomplished in a uniform gradual che...