U.S. Philips Corporation

Other

Frederik Ate De Jonge

Antonius G Verhulst

Willem Frederik Druyvesteyn

Jan Willem Dorleijn

Gerrit J Koel

Willem Frederik Druijvesteijn

A magnetic device comprising at least one thin layer of a magnetizable material which has an easy axis of magnetization approximately normal to the surface of the layer. Magnetic domains are propagated in the layer by a rotating magnetic field in co-operation with a pattern of magnetizable material on the layer. Domains are detected by passing a current through a pattern of magneto-resistive material on the layer. At least in the part of the device where the detection occurs, the propagation and detection patterns have substantially the same configuration and one pattern is situated between the layer of magnetizable material and the other pattern.

Magnetic domain device

A device for reading information-representing magnetization patterns by means of a magneto-resistive element. The magneto-resistive element is in magnetic flux coupling with a plurality of magnetization patterns simultaneously. A desired portion of the element is selected for reading by influencing such portion by the external magnetic field of a magnetic bubble domain. Information positions can be read in sequence by moving the bubble domain along magneto-resistive element.

Magneto-resistive detector with scanning bubble domain

The invention relates to a device for magnetic recording which is provided with a layer of a magnetizable material which is provided on a support and has an easy axis of magnetization which is at least substantially perpendicular to the plane of the layer, which layer is suitable to support magnetic domains having a direction of magnetization which is opposite to the direction of magnetization of the remainder of the layer, the device also comprising a device for producing a magnetization field having a field direction perpendicular to the plane of the layer, said layer being destined to cooperate with a recording medium which is relatively movable with respect to the layer.

Device for the magnetic recording by means of a magnetic strip domain as

A recording device for storing and playing back information in which mechanical deformations which are representative of the stored information are provided in the surface of a record carrier consisting of a permanent magnetizable material or being covered with such a material. As a playback element is present a sheet of monoaxial magnetizable material which comprises a single-walled magnetic domain ('bubble'). The size of the domain is modulated upon moving the recording medium with respect to the sheet. Deposition of the domain in the sheet upon playing back can be corrected by way of fine control.

Record carrier and device for playing back same

A recording device in which hollow magnetic domains are produced in plates of, for example, orthoferrite by means of a magnetic field. The region within which the field can vary without said domains disappearing depends upon the coercive force of the material. Field variations cause a particular irreversible variation in the domain dimensions, provided a certain minimum coercive force is present. In particular, in order to increase the stability of a hollow domain, a single-walled domain is present within it.

Hollow magnetic domain recording device

A magnetic device comprising a first and a second plate of a magnetic material between which domains are situated. An interaction force occurs between the domains in the two plates. Stable domain positions in a second plate define equally stable domain positions in a first plate. One or both plates can be provided with domain guiding structures. Domain displacement in one plate can control a domain displacement in the other so that a variation in the interaction force is produced.

Magnetic domain logic device

A device for recording and playing back information in a spiral-like track or a track consisting of concentric circles present on a disk-shaped recording medium, in which the storage and playback element consists of a sheet of magnetizable material which contains a single-wall magnetic domain. The polarity of a radially directed magnetic field can be inverted according to a frequency modulated with a signal to be recorded so as to record information together with the stray field of the domain. A detector is present to detect position variations of the domain upon playing back and means are present to correct the position of the domain in the sheet by way of fine control upon playing back.

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Eindhoven, Netherlands

Frederik Ate De Jonge