U.S. Philips Corporation

Dirk J Breed

Antonius B Voermans

John M Robertson

Bernardus A Van Bakel

Hans Logmans

A device for propagating magnetic domains includes a monocrystalline nonmagnetic substrate of a rare earth gallium garnet bearing a layer of an iron garnet capable of supporting local enclosed magnetic domains. The iron garnet layer is grown in compression on a (100) face of the nonmagnetic substrate. The iron garnet comprises manganese in part of the iron sites of its crystal lattice, and comprises yttrium and at least one representative selected from the group comprising bismuth and the rare earth metals in the dodecahedral lattice sites. Such a magnetic garnet has a very high uniaxial anisotropy and a high domain mobility. These properties make the device extremely suitable for propagating submicron magnetic domains having diameters as small as 0.4 .mu.m.

Device for propagating magnetic domains

A device for propagating magnetic domains, comprising a monocrystalline nonmagnetic substrate of a material having a garnet structure, and a layer of an iron garnet grown epitaxially on the nonmagnetic substrate. In the dodecahedral lattice sites, the iron garnet comprises at least a bismuth ion and a rare-earth ion selected from the group consisting of lutetium, thulium, and ytterbium. Such a magnetic garnet combines very high uniaxial anisotropy with a high domain mobility, which properties make the device extremely suitable for the propagation of magnetic domains having diameters from approximately 1 to approximately 2 .mu.m under the influence of comparatively low driving fields.

A magnetic structure in which magnetic domains can propagate. The structure comprises a monocrystalline gallium garnet substrate having a surface which is substantially parallel to a (100) crystal plane and on which a layer of rare-earth iron garnet, having a partial substitution of maganese ions in iron sites, is grown in compression. By using a substrate material having a lattice constant between 12.23 and 12.38 .ANG., the compression of a epilayer having certain desired magnetic properties can be adjusted by adjusting the incorporation of lutetium and yttrium ions in the epilayer, without adversely affecting magnetic properties of the layer.

Magnetic structure suitable for the propagation of single-walled

A magnetic domain device comprising a layer of a magnetic material for the formation of magnetic domains, for example bubbles, under the influence of a bias magnetic field and a propagation structure with magnetically operating elements for driving the magnetic domains by the sequential formation thereon of preferred positions for the domains. The current conductors used to propagate the domains, either meander conductors or rotary field 'coils', are arranged on a layer of silicon, so that the heat developed in the current conductors can readily be carried off by the silicon which exhibits a good thermal conductivity.

Magnetic bubble-domain device

A magnetic structure having a high magnetic bubble mobility which has the property that magnetic bubbles can be transported in it at very high velocities while using comparatively weak driving fields, comprising a substrate having a (110) oriented deposition surface on which a layer of rare earth -- iron garnet with a substitution of Mn.sup.3+ in iron lattice sites has been grown in compression in such a manner that the layer of rare earth-iron garnet has an orthorhombic anisotropy.

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Eindhoven, Netherlands

Dirk J Breed