Browse Prior Art Database

Maximization of Usable Bubble Domain Platelet Area

IP.com Disclosure Number: IPCOM000074240D
Original Publication Date: 1971-Apr-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Lin, YS: AUTHOR [+3]

Abstract

A bubble domain platelet of finite extent has a highly nonuniform demagnetizing field. This field is maximum at the center of the platelet and decreases towards the edges of the plateler. The stability of bubble domains is determined by the balance of forces due to the normal bias field H(Z), the demagnetizing field Hd of the platelet, and the domain wall energy. Accordingly, for a finite orthoferrite platelet, a nonuniform bias field is required to compensate for the nonuniform demagnetizing field of the platelet.

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Maximization of Usable Bubble Domain Platelet Area

A bubble domain platelet of finite extent has a highly nonuniform demagnetizing field. This field is maximum at the center of the platelet and decreases towards the edges of the plateler. The stability of bubble domains is determined by the balance of forces due to the normal bias field H(Z), the demagnetizing field Hd of the platelet, and the domain wall energy. Accordingly, for a finite orthoferrite platelet, a nonuniform bias field is required to compensate for the nonuniform demagnetizing field of the platelet.

Fig. 1 shows an orthoferrite platelet 10 of finite extent while Fig. 2 shows the demagnetizing field Hd associated with this platelet. Hd is nonuniform and it is probable that less than 60% of the platelet area will be stable for bubble domains if the bias field H(Z) is uniform. To fully utilize platelet 10, HI is adjusted to compensate for the nonuniform demagnetizing effect. A means for doing this is shown in Fig. 3 where a permanent magnet 12 is used to provide the bias field. The dimension and shape of magnet 12, and the platelet magnet spacing is adjusted so that the contour of the magnetic field produced by magnet 12 resembles the demagnetizing field contour of the platelet.

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