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Composite Cylindrical Magnetic Domain Materials

IP.com Disclosure Number: IPCOM000074241D
Original Publication Date: 1971-Apr-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Ahn, KY: AUTHOR [+2]

Abstract

A composite material for cylindrical magnetic domains is shown having two layers. This composite structure yields cylindrical domains which have properties determined by the properties of the individual layers in the composite structure.

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Composite Cylindrical Magnetic Domain Materials

A composite material for cylindrical magnetic domains is shown having two layers. This composite structure yields cylindrical domains which have properties determined by the properties of the individual layers in the composite structure.

A layer of orthoferrite of thickness h(1) has a layer of MnBi or magnetoplumbite of thickness h(2) located over it. The normal diameter for cylindrical domains in the orthoferrite is d(1) while the normal diameter for cylindrical domains in the MnBi or magnetoplumbite is d(2). These films are in intimate contact. To achieve a straight cylindrical domain in the composite structure, the product of saturation magnetization M and layer height hl for the orthoferrite layer and the MnBi (or magnetoplumbite) layer should be comparable. That is, M(1)h(1) should be as close as possible to M(2)h(2) in order that there be perfect magnetostatic and exchange coupling between the two layers. The resultant domain diameter d would then be equal to the square root of d(1) x d(2).

Both layers possess uniaxial anisotropy having an easy axis perpendicular to a surface of the layers. This composite structure may be fabricated by several techniques, including vapor deposition and vacuum evaporation of MnBi (or co- deposition of MnBi). As an example, the underlaying orthoferrite crystal is properly polished followed by heating in vacuum up to 300 degrees C for outgassing and cleaning. Single crystal films...