U.S. Philips Corporation

Ulrich E Enz

Jan Haisma

Jacobus J Ruigrok

Victor Zieren

Willem Frederik Druyvesteyn

Klaas L Van Mierloo

Antonius G Verhulst

Albert A Comberg

Hendrik J De Wit

Albertus J Van Der Borst

Leonardus A Van Hoof

Marcel Brouha

Evert H Dekker

Piet F Bongers

Doeko Stoppels

Cornelis W Sillen

Gijsbertus W Turk

Peter G Boonen

Kornelis Jager

Norbert E Hansen

Device is provided for reading information from a magnetic recording medium, comprising a SQUID (15), a magnetic yoke formed from two flux guides (3 and 5) and a face (13) for magnetic flux coupling of the SQUID with the magnetic recording medium. The SQUID is provided with connection means (33) for a detection circuit (35).

Superconducting device for reading information from a magnetic recording

Thin-film magnetic head including an inductive transducing element (15) and a face (3) for magnetic flux coupling of the transducing element with a magnetic recording medium. A first magnetically permeable layer (5) and a second similar layer (7) together constitute a transducing gap (11). To improve the transducing function a layer (21) of a superconducting material is provided between the layers (5) and (7).

Thin-film magnetic head including an inductive transducing element

An electroacoustic transducer comprises a terminal (1-1'), a voice coil (2) coupled to the terminal, and a diaphragm (4). The transducer further comprises an element (other than the voice coil) made of a superconducting material which cooperates with the voice coil (2) to provide electromechanical conversion of an electric signal appearing at the terminal (1-1') into vibrations of the diaphragm, or vice versa.

Electroacoustic transducer comprising a superconducting element

Magnetic head for reading information from a magnetic registration medium. Comprises a magnetic yoke (3) having two limbs (3A, 3B) whose free ends constitute pole faces (3A1, 3B1) on either side of a read gap (7). A magnetoresistive element (15A, 15B) provided within the magnetic yoke at a distance from the pole faces is constituted by a layer of Bi provided on the magnetic intermediate yoke (13). Viewed in the longitudinal direction of the read gap, the layer of Bi extends on either side of this gap and at least during operation it is in a constant magnetic field directed transversely to the layer of Bi.

Magnetic head with magnetoresistive element

Magnetic transducing head comprising a magnetic core having two core limbs (1, 3) formed from a ferrite, a non-magnetizable gap (11) extending between two core faces (1B, 3B) of the core limbs and an electric coil (7) passing through a winding aperture (5). A cladding consisting of a first layer (13) of an Ni-Fe-based alloy is provided on at least one of the core faces, and a second layer (15) of an Fe-Si-Al-based alloy which is provided on the first layer.

Magnetic transducing head having clad core faces

A magnetic head having a core of a magnetizable material around a part of which a coil is provided. A transducing gap is formed between two core parts of a magnetically anisotropic, amorphous ferromagnetic metal. The core parts of a magnetically anisotropic, amorphous ferromagnetic material have a magnetic anisotropy direction induced by a thermal treatment in a magnetic field which is in the plane of the core parts and encloses an angle .alpha. with the direction in which magnetic flux traverses the core parts during operation. .alpha. preferably is equial to 90.degree.. By these means an increased permeability in the MHz range is reached in combination with a minimum loss component.

Magnetic head with anisotropy in plane of core ports

A magnetic head for a magnetic recording and playback device includes a core having two core parts which are spaced from each other and between which a transducing gap is formed. The core consists of a (preferably monocrystalline) zinc-ferrous ferrite. A preferred range of compositions is defined by the formula

Magnetic head having cobalt-containing zinc-ferrous ferrite core

A magnetic bubble domain structure comprising a bubble domain layer supported by a nonmagnetic substrate. A control layer is superimposed on the major surface of the domain layer which remote from the substrate. The control layer has an easy axis of magnetization in the plane which defines at least one bubble domain propagation path. The unique control layer according to the invention may be a garnet layer which comprises two sublayers: a first, continuous, sublayer, and a second, discontinuous, sublayer. The discontinuous sublayer defines the required propagation patterns. An advantage of the invention is that the in-plane rotary field to be applied for propagating the bubble domains can be considerably weaker than in bubble domain structures which are equipped with nickel-iron propagation patterns.

Magnetic bubble domain structure

A magnetic device comprising at least one thin domain layer of a magnetizable material which has an easy axis of magnetization which is substantially normal to the surface of the layer and in which magnetic domains are propagated under the influence of a bipolar current, for example an alternating current, by a pattern of electrically conductive material with which the layer is provided. Elements are furthermore present which cause an asymmetry force and thus determine the direction in which the domains are propagated. The electrically conductive material and the elements are present in a single pattern which is constructed from at least a layer of magnetic material.

Magnetic domain device

A magnetic bubble device comprising a non-magnetic substrate layer, and a sequence of magnetic layers joined to each other and to the magnetic substrate layer, e.g. by epitaxial growing of crystalline layers, whereby at least two of the magnetic layers may accommodate magnetic bubbles which are stably joined through an interlayer magnetic compensation wall, or by an essentially finite potential barrier.

Magnetic bubble multilayer arrangement

A method of manufacturing a magnetizable layer having domains with at most two Bloch walls for a magnetic domain device in which a monocrystalline layer of Y.sub.3.sub.-x La.sub.x Fe.sub.5.sub.-Y Ga.sub.Y O.sub.12, wherein 0.1 .ltoreq. .times. .ltoreq. 0.2 and 1.0 .ltoreq. Y .ltoreq. 1.5 is provided on a monocrystalline substrate and is covered with an SiO-containing layer after which the monocrystalline layer is maintained at a temperature between 300.degree. C and 600.degree. C for some time.

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Eindhoven, Netherlands

Ulrich E Enz