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Single Layer Bubble Film Containing Bistable States

IP.com Disclosure Number: IPCOM000083612D
Original Publication Date: 1975-Jun-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Hsu, TL: AUTHOR [+2]

Abstract

The present method of coding in bubble lattice systems are based on the existence of at least two different wall states, for example, the S=0 and S=1 wall states. A primary problem is maintaining the stability of both the S=0 and the S=1 wall states in a given system. Usually under a given set of conditions, one wall state is unstable while the other state is stable.

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Single Layer Bubble Film Containing Bistable States

The present method of coding in bubble lattice systems are based on the existence of at least two different wall states, for example, the S=0 and S=1 wall states. A primary problem is maintaining the stability of both the S=0 and the S=1 wall states in a given system. Usually under a given set of conditions, one wall state is unstable while the other state is stable.

One approach to solving this problem is by the use of a capping layer film in which an in-plane magnetic field, for example, 25 oersteds is continuously applied to a magnetic layer which is exchange coupled to the medium containing bubble domains. The magnitude of the magnetic field that is applied is greater than 0 oersteds, and less than that required to obtain a bubble domain having a pair of Bloch lines therein.

As an alternate approach to solving this problem, it is proposed that the film of bubble domain material have a Q value of between one to three and preferably between two to three. The Q value is the ratio of the anisotropy field, H(k), to the saturization magnetization, 4 pi M(s), and given by the equation Q=H(k)/4 pi M(s).

From the consideration of suppression of hard bubbles, a low Q film is very similar to a triple-layered film. In a triple-layered film, the layer that contains magnetic bubble domains is sandwiched between two layers with in-plane magnetization.

When Q is in the range of one to three and particularly between two and ...