U.S. Philips Corporation

Christoph Schmelzer

Jens-Peter Krumme

Klaus Witter

Heinrich Heitmann

Reimar Spohr

A magnetic layer for storing information in the form of a fixed, two-dimensional array of magnetic domains. The magnetic layer can be magnetized in either of two opposite directions normal to the plane of the layer. The walls of the domains are fixed by local gradients in the value and direction of the magnetic anistropy and in the value and direction of the magnetic exchange energy of the magnetic layer. The local gradients may be caused by a relatively high defect density at the domain wall locations, by implanting ions into the magnetic layer at the locations of the domain walls thereby causing a local expansion of the crystal lattice of the layer, and/or by etching a multiplicity of nonconnected tapering channels in and substantially perpendicular to the plane of the magnetic layer at these locations. Where tapering channels are used, the magnetic layer is provided on a substrate such that the crystal lattice constant of the magnetic layer is different from the crystal lattice constant of the substrate. In another embodiment, the local gradients can be the result of the epitaxial growth of a magnetic layer on a substrate which has a plurality of nonconnected etched channels at the domain wall locations.

Method of making a magnetic memory layer

A magnetic layer for storing information in the form of a fixed, two-dimensional array of magnetic domains. The magnetic layer can be magnetized in either of two opposite directions normal to the plane of the layer. The walls of the domains are fixed by local gradients in the value and direction of the magnetic anisotropy and in the value and direction of the magnetic exchange energy of the magnetic layer. The local gradients may be caused by a relatively high defect density at the domain wall locations, by implanting ions into the magnetic layer at the locations of the domain walls thereby causing a local expansion of the crystal lattice of the layer, and/or by etching a multiplicity of non-connected tapering channels in and substantially perpendicular to the plane of the magnetic layer at these locations. Where tapering channels are used, the magnetic layer is provided on a substrate such that the crystal lattice constant of the magnetic layer is different from the crystal lattice constant of the substrate. In another embodiment, the local gradients can be the result of the epitaxial growth of a magnetic layer on a substrate which has a plurality of non-connected etched channels at the domain wall locations.

Growing community of inventors

Munich, Georgia

Christoph Schmelzer