U.S. Philips Corporation

Lambertus Postma

Jan Haisma

Gerardus H Somers

Jacobus J Ruigrok

Pieter Jan Van Der Zaag

Gerrit J Koel

Ronald Martin Wolf

Jacobus J M Ruigrok

Thijs W Bril

Wiepke Folkerts

Johannes F M Cillessen

Henricus G Maas

Gijsbertus A Spierings

Gerardus J Lippits

Waltherus W Van Den Hoogenhof

Poul K Larsen

Cornelis L Adema

Cornelis H Witmer

Peter W De Haas

Mathijs P Souts

Dirk K De Boer

Jan B Van Der Putten

Arie J Van Straalen

Johannes M Busio

Casper Johannes Janssen

Frederik H In 't Veld

Pieter Dekker

Thin-film magnetic head having a head face (,) and comprising a magnetoresistive element (,) oriented transversely to the head face and a flux-guiding element (,) of a magnetically permeable material terminating in the head face. A peripheral area (,) of the magnetoresistive element extending parallel to the head face is present opposite the flux-guiding element for forming a magnetic connection between the magnetoresistive element and the flux-guiding element. The flux-guiding element and the peripheral area of the magnetoresistive element constitute a common magnetic contact face (,), while the magnetically permeable material of the flux-guiding element is electrically insulating.

Method of manufacturing a magnetic head

Thin-film magnetic head and method of manufacturing the magnetic head

Method of providing a pattern of apertures and/or cavities in, for example, a glass duct plate of a plasma-addressed liquid crystal display, in which first a mechanical treatment is performed (for example, by means of powder blasting) and then a wet-chemical etching treatment is performed to render the walls of the ducts microscopically less rough so that the optical disturbance is reduced and the glass becomes clearer again.

Method of post-etching a mechanically treated substrate

Magnetic head having a multilayer structure which comprises at least one magnetoresistive layer (9) and a transducing gap terminating in a head face. The magnetoresistive layer has an active central portion located between two end portions, which central portion is provided with equipotential strips (13). Layers (15) of a hard-magnetic material with an axis of magnetization extending in the longitudinal direction of the magnetoresistive layer are provided opoosite to, and spaced apart from the end portions, a non-magnetic spacer layer (17) of electrically insulating material being present between the end portions and said layers of hard-magnetic material.

Magnetic head having a multilayer structure and method of manufacturing

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

Method of manufacturing a thin-film magnetic head provided with a transducing element (23) and at least one flux-guiding element (17a, 17b). An electrically conducting layer (8) of a non-magnetic material and a second electrically insulating layer (9) of a non-magnetic material are successively formed on a first electrically insulating layer (5) of a non-magnetic material. The second electrically insulating layer is subsequently provided with at least an interruption exposing a portion of the electrically conducting layer. Subsequently, the flux-guiding element is formed by electrodepositing a soft-magnetic material on said portion until the interruption is filled, whereby the flux-guiding element and the second electrically insulating layer constitute an at least substantially plane surface on which an electrically insulating spacer layer (21) is formed. Subsequently, the transducing element is provided on the spacer layer. The magnetic head thus formed has a non-magnetic transducing gap (35) terminating in a head face (33) and being constituted by the first electrically insulating layer (5) and the electrically conducting layer (8).

Method of manufacturing a thin-film magnetic head, and magnetic head

Method of polishing a surface (5a) of a noble metal or an alloy comprising mainly noble metal, in which a polishing means is moved across the surface while exerting a polishing pressure for obtaining a plane and smooth polished surface without any defects. A composition comprising demineralized water with 20 to 40% by weight of an organic liquid comprising a poly-alcohol or a derivative thereof, for example, glycerol, and particles which can be encapsulated and have a Knoop's hardness of between 5 and 50 GPa, for example Al.sub.2 O.sub.3 grains, is used as a polishing means.

Method of polishing a surface of a noble metal

Method of polishing a surface (5a) of copper or an alloy comprising mainly copper, in which a polishing means is moved across the surface while exerting a polishing pressure of approximately 500 g/cm.sup.2 for obtaining a plane and smooth polished surface without any defects. A composition of a polishing component comprising a colloidal suspension of SiO.sub.2 particles having an average particle size of between 20 and 50 nm in an alkali solution, demineralized water and a chemical activator is used as a polishing means.

Method of polishing a surface of copper or an alloy comprising mainly

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

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 magnetic head (1) having two core parts (2,3) of a magnetic material between which a non-magnetic transducing gap (4) is formed which has a central part (21) having a gap length which is selected to transduce the carrier frequency of a video signal and having a width which is defined by first and second side gaps (22,23) having gap lengths which are selected to suppress the carrier frequency of a video signal, the first and second side gaps (22,23) being bounded by indentations (7,8) in the sides of the core parts (2,3) and being filled with a material which bonds the two core parts (7,8) together.

Magnetic head having a step-shaped gap

A magnetic head having an elongate magnetoresistive element bearing a pattern of equipotential strips extending obliquely to its longitudinal axis for adjusting a suitable workpoint. With its edges extending parallel to the longitudinal axis, the element bears on components of magnetically permeable material one of which, in operation, is in direct flux coupling with a magnetic recording medium and the other of which is in flux coupling with the recording medium via a further element of magnetically permeable material which may be ferrite.

Magnetoresistive head

In the electrodeposition of nickel-iron alloy layers during the manufacture of a thin-film magnetic head it is ensured that the nickel-iron alloy layer has a top layer having a higher iron content than the iron content of the remainder of the nickel-iron alloy layer. Since this top layer etches more rapidly than the remainder of the layer, the nickel-iron alloy layer itself becomes sloped during etching, this sloping configuration presents great advantages in the subsequent coating with a layer of silicon dioxide.

Method of manufacturing a thin-film magnetic head with a nickel-iron

A method of manufacturing a magnetic device for propagating and detecting magnetic domains. At least one thin domain layer of a magnetizable material is provided on a nonmagnetic substrate body and hereon are provided a number of layers of which there are at least a detection layer of magnetoresistive material and a layer of electrically insulating nonmagnetic material. The latter is provided with a propagation layer of magnetizable material in a pattern which satisfies the requirements of propagation of magnetic domains and the requirements of detecting magnetic domains. The non-covered parts of at least the layer of electrically insulating, nonmagnetic material and of the layer of magnetoresistive material are successively removed, each time by means of a method which does not substantially attack the pattern of the material present above the relevant layer.

Method of manufacturing a magnetic device

A method of making inclined sides on a metal pattern which is grown on a substrate by electroplating as a preliminary measure to the coating of the substrate with the metal pattern by an insulating layer. The main deposition of the insulating layer by sputtering is preceded by a sputter-etching step which transforms the rounded edges of the metal pattern into inclined sides.

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Eindhoven, Netherlands

Lambertus Postma