U.S. Philips Corporation

Jacobus J Ruigrok

Victor Zieren

Gerardus H Somers

Lambertus Postma

Ulrich E Enz

Jan Haisma

Franciscus W Dirne

Cornelis W Sillen

Pieter Jan Van Der Zaag

Henricus G Maas

Hans Willem Van Kesteren

Reinder Coehoorn

Jacobus Bernardus Giesbers

Adrianus P Severijns

Willem Frederik Druyvesteyn

Frederik W Gorter

Ulrich Traxlmayr

Franciscus A Pronk

Wiepke Folkerts

Martinus A Gijs

Marinus L Vrinten

Mathijs De Jongh

Jacques C Kools

Arnold Broese Van Groenou

Wolfgang Binder-Krieglstein

Pascal Jh Bloemen

Johannes A Van Ooijen

P Michalek

Andre A Verhulst

Casper M Smit

Jean-Paul G Morel

A method for creating a magnetically permeable film on a substrate surface by deposition of successive layers of a magnetic material, during deposition of each layer a magnetic field being provided near said surface having a field direction substantially parallel to the surface. In order to tune the permeability of the magnetic material the method builds up the magnetically permeable film by forming each layer by depositing a ferromagnetic material to a thickness maximally corresponding to substantially ##EQU1## where L.sub.ex is equal to ##EQU2## with A being the exchange constant of the ferromagnetic material and K.sub.u being the uniaxial anisotropy constant, and changing the magnetic field direction during formation of said layer by an angle other than substantially 180.degree..

Methods for creating a magnetically permeable film

An element of an apparatus is magnetized so as to generate a magnetic field pattern around the element. To achieve this, use is made of a magnetizing coil, and the element and the magnetizing coil are moved relative to each other, the magnetizing coil carrying an alternating current of substantially constant amplitude as well as a signal current. Preferably, there is a phase difference between the signal current and an intended magnetic field pattern.

Method of manufacturing a magnetic device

Single-channel magnetic head having a head face (1) which extends in a first direction (I) in which a magnetic record carrier (3) is relatively movable with respect to the magnetic head, and in a second direction (II) transverse to the first direction. The magnetic head has a structure of layers which, viewed in the first direction, are situated one on top of the other and extend substantially in the second direction and a third direction (III) transverse to the first and the second direction. The structure is provided with a magnetoresistive measuring element (5), a first magnetic element (7) and a second magnetic element (9). Both magnetic elements are electrically conducting, while the measuring element is arranged electrically in series between the two magnetic elements for passing a measuring current (i) through the measuring element substantially in the third direction. Each magnetic element has an electric contact face (7a, 9a). To obtain a stable single-channel magnetic head having a narrow, well-defined scanning width, at least one magnetic element extending as far as the head face has an extensiveness which is larger in the second direction than in the third direction. This extensiveness in the second direction is also larger than the effective width (w) of the measuring element. In the third direction, the relevant magnetic element has a larger relative magnetic permeability (.mu..sub.rIII) than in the second direction.

Single-channel magnetic head with magnetoresistive element in series

System comprising a magnetic head (1) and a measuring device connected to the magnetoresistive element. The magnetic head has a head face (5) with a transducing gap (15) and comprises a magnetoresistive element (13) and a magnetically conducting yoke with an electrically conducting element (11a) for generating a magnetic field intersecting the magnetoresistive element. The system also comprises a current device connected to the electrically conducting element.

System comprising a magnetic head, measuring device and a current device

Magnetic head having a head face (1) and comprising a multilayer structure with a flux guide (7a, 7b), a magnetoresistive sensor (9) and an intermediate layer (13) present between the flux guide and said sensor. The intermediate layer comprises an anti-ferromagnetic oxide which insulates the sensor from the flux guide and also magnetically biases the sensor.

Magnetic head with magnetoresistive sensor, and scanning device provided

Scanning head including a magneto-optical element and scanning device including the scanning head. A scanning head having a head face (1) comprises flux-guiding elements (3a, 3b) and a magneto-optical element (5). The magneto-optical element is disposed in a gap plane (4) which extends between flux-guiding elements.

Scanning head including a magneto-optical element and scanning device

A device for detecting a magnetic field, which device comprises a magneto-resistive multilayer structure comprising a first magnetic layer (1) which is separated from a second magnetic layer by an interposed non-magnetic layer, the multilayer structure having a first in-plane reference axis (R.sub.1) coinciding with the direction in which magnetic flux is offered to the multilayer structure during operation, and a second in-plane reference axis (R.sub.2) which is perpendicular to the first reference axis (R.sub.1), whereby the magnetic easy axis (E.sub.1) of the first magnetic layer (1) is canted through an acute in-plane angle .alpha. with respect to the second reference axis (R.sub.2), and the magnetic easy axis (E.sub.2) of the second magnetic layer is canted in the opposite sense through an acute in-plane angle .beta. with respect to the second reference axis (R.sub.2). Such a device lends itself to application in a magnetic head, for sensitive retrieval of magnetically-encoded data from a carrier in the form of a tape, disc or card.

Magnetic field sensor

Method of manufacturing a thin-film magnetic head in which a main layer (5) of a non-magnetic material is formed on a support, which layer is recessed by removing material from a side remote from the support, said recess being subsequently filled up with a soft-magnetic material for forming a flux guide (17a, 17b), whereafter the main layer provided with the filled recess is mechanochemically polished for forming a main surface (19) at which subsequently a layer of a magnetoresistive material is provided for forming a magnetoresistive element (23).

Method of manufacturing a thin-film magnetic head

Magnetic head unit comprising a magnetic head secured in a housing and having a magnetic head structure provided with a head face and at least one transducing gap terminating in the head face. A wear- resistant layer (31 ) having at least one alignment mark (35, 36, 37) occupying a defined position with respect to the transducing gap is provided on the head face.

Magnetic head with wear resistant layer having alignment mark, and

Method of manufacturing a magnetoresistive magnetic head in which a first insulation layer (5) of a non-magnetic material is formed on a support face (3a), on which insulation layer a soft-magnetic layer having an upper face remote from the first insulation layer is formed by deposition of a soft-magnetic material. Subsequently a layer portion is removed for forming the flux-guiding elements (17a, 17b) and an aperture extending between said elements, and non-magnetic material for forming a second insulation layer (18) having an upper face remote from the soft-magnetic layer is deposited on the soft-magnetic layer and in the aperture formed therein, which second insulation layer has such a thickness that, viewed in a direction transverse to the support face, the smallest distance between the support face and the upper face of the second insulation layer is larger than the largest distance between the support face and the upper face of the soft-magnetic layer. Subsequently, a mechanochemical polishing treatment is performed as from the upper face of the second insulation layer for forming a main surface (19) at which magnetoresistive material is subsequently deposited for forming a magnetoresistive element (23).

A method of manufacturing one or more magnetic heads starts from a substrate (11) on which a first magnetic layer (13) is provided. A recess (15) is formed in this layer at the location of a transducing gap to be formed, after which a gap layer (19) is provided on a bounding wall (17) of the recess. Subsequently, the recess is filled with a second magnetic layer (23) and a counterblock (31) is provided on the layers after surface-polishing. Finally, a winding aperture is provided.

Method of manufacturing a magnetic head

Combined read/write thin-film magnetic head comprising a read portion including a magneto-resistive element, a write portion including an inductive element, and a shared flux guide between the read and write portions. Improved separation of the read and write functions is achieved by providing the shared flux guide as a sandwich structure of two soft magnetic layers separated by an insulating layer, except that the soft-magnetic layers are interconnected in a magnetically conducting manner proximate to the head face.

Combined read/write thin-film magnetic head with composite shared flux

Thin-film magnetic head comprising a substrate (3), a magnetoresistive element (9) and two magnetically conducting flux guides (5, 7) extending substantially parallel to each other for magnetic cooperation with the magnetoresistive element (9). A non-magnetic read gap (13) adjacent to a head face (1) extends between the flux guides. The first flux guide (5) is built up in layers and comprises a first soft-magnetic layer (5A) opposite the second flux guide (7), a second soft-magnetic layer (5B) and an insulation layer (5C) of a non-magnetic material extending substantially parallel to the substrate and situated between these soft-magnetic layers. Said soft-magnetic layers join in a common end portion (5E) proximate to the head face. The first soft-magnetic layer is an interrupted layer having two spatially separated layer portions (5AA, 5AB), bridged by the magnetoresistive element.

Thin-film magnetic head

Thin-film magnetic head comprising a substrate (2), an inductive element (23) and a magnetoresistive element (7), and substantially parallel extending flux guides of a magnetic conducting material for magnetic cooperation with said elements. The flux guides are mutually arranged in such a way that two pairs of flux guides (3A, 3B; 5A, 5B) mutually separated by an insulation layer (19) of a non-magnetic material are present, a first pair constituting a first magnetic circuit, provided with a write gap (27), for the inductive element and a second pair constituting a second magnetic circuit, provided with a read gap (17), for the magnetoresistive element.

Combined read/write thin film magnetic head with two pairs of flux guides

Magnetic head comprising a magnetic core having two core limbs (1,3) formed from a ferrite, which core limbs constitute two core faces located opposite each other, at least one of said core faces having a cladding of a soft-magnetic material having a higher saturation magnetisation than the ferrite, and a non-magnetic transducing gap (11) present between the core faces and having at least one layer of a first metallic material (21) and bonded layers (23) of a second metallic material. The cladding comprises a first cladding layer (15) of an alloy based on Ni-Fe on which a second cladding layer (17) of an amorphous alloy based on Co-Ti and/or Zr and/or Hf-Nb and/or Ta is provided, while the first metallic material, chosen from the group of Mo, Ti, Cr and NiCr, is directly provided on the amorphous alloy of the cladding. (FIG. 2).

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Eindhoven, Netherlands

Jacobus J Ruigrok