Sumitomo Special Metals Co., Ltd.

Nippon Tungsten Co., Ltd.

Sumitomo Special Metal Co. Ltd.

Citizen Watch Company, Ltd.

Nippon Hoso' Kyokai

Toshiaki Wada

Michito Miyahara

Mitsuhiko Furukawa

Masaharu Shiroyama

Yoshiaki Katsuyama

Junichi Nakaoka

Takashi Kitahira

Kiyohito Misumi

Mitsuyoshi Nagano

Shigeki Mohri

Hideki Mine

Akio Murata

Toyoshige Sasaki

Masateru Nose

Naoki Fujii

Toshikazu Hatsuse

Osamu Nakano

Naoto Hayashi

Shinji Tsujimoto

Shigehiro Fuwa

Junji Numazawa

Shin Mishima

Shigeru Kawahara

Masaru Ito

Seiichi Hirao

Mitsuhiki Furukawa

Shigeki Mori

Takayuki Sugano

Takayuki Ono

Substrate materials for magnetic heads consisting of 24-75 mol % of .alpha.-Al.sub.2 O.sub.3 and the remaining 76-25 mol % of TiC.sub.x O.sub.y N.sub.z containing a small amount of additives, that has a NaCl-type structure which retain known characteristics required on such materials and have controlled sizes of crystallites of Al.sub.2 O.sub.3 and TiC.sub.x O.sub.y N.sub.z, uniformly dispersed TiC.sub.x O.sub.y N.sub.z crystallites and, if any, additive elements, in which internal stress is relieved. The materials are intended for eliminating problems in IBE to form steps and thus for fabricating high-precision thin-film heads for high-density recording.

Substrate materials for magnetic head

A material for a magnetic head slider consists essentially of 0.1 to 20.0 vol % of at least one of oxides the group Va elements of the International Periodic Table (Ta, Nb, V) and 80.0 to 99.9 vol % of stabilized cubic ZrO.sub.2 containing a stabilizer (Y.sub.2 O.sub.3, MgO, CeO.sub.2). It has improved precision machinability, machining efficiency, high strength, densified structure, affinity with the recording medium or lubricity, besides wear resistance. It may be machined precisely into a thin film magnetic head slider with a reduced amount of chipping.

Magnetic head slider material

A sintered material for recording/reading (particularly magnetic) head slider is produced by:

Process for the production of magnetic head sliders

A perpendicular magnetic recording/reproducing thin film head of the single pole type formed of a magnetic member provided on its main surface with a grooved portion, and a non-magnetic material filled in the grooves of the grooved portion, thin film conductor coils, an inter-layer insulation film and a main magnetic pole film, wherein at least the thin film conductor coils, the inter-layer insulation film and the main magnetic pole film are laminated on the magnetic member to form a return path. The magnetic member and the main magnetic pole film are connected at the return path and the thin film head has an exposed laminated end face adapted to be opposed to a recording medium and the magnetic member forming a return path appears on the exposed laminated end face and is formed with a portion having the same width as that of the main magnetic pole film and arranged in parallel with the main magnetic pole film and the remaining portions other than the parallel portion are arranged in non-parallel relationship with the main magnetic pole film.

Magnetic thin film head of a single magnetic pole for perpendicular

A thin film magnetic head for perpendicular magnetic recording includes a magnetic member lying on a wear-resistant substrate of a non-magnetic material and defining a return path for magnetic flux. The magnetic member has a main groove formed in one of its principal surfaces in parallel to a sliding surface adapted to face a magnetic recording medium, and a narrow groove formed in the same principal surface and crossing the main groove at right angles thereto. The main and narrow grooves are filled with a non-magnetic material. The magnetic member carries thereon a laminate formed immediately above the intersection of the main and narrow grooves, and consisting at least of a thin-film conductor coil, an interlayer insulating film, a main pole film and a head-protecting film which are formed one upon another. The narrow groove has a width which is larger than that of the main pole film. The magnetic member is connected to the main pole film through a via hole portion. The magnetic member and the laminate have an exposed surface defining the sliding surface, and the magnetic member is exposed in the vicinity of the main pole film.

Thin-film magnetic head for perpendicular magnetic recording having a

A thin-film magnetic head includes a magnetic member having a principal surface formed with a first groove extending in parallel to a sliding surface adapted to face a magnetic recording medium, a non-magnetic material filling the groove, and at least a thin-film conductor coil, an interlaminar insulating film, a main magnetic-pole film and a protective film formed one upon another. The magnetic member being connected to the main magnetic-pole film though a via hole portion. The head has an exposed laminated surface defining the sliding surface. The magnetic member has also a second groove formed in its principal surface, crossing the first groove at right angles thereto, and filled with a non-magnetic material. The conductor coil and films are formed on the magnetic member immediately above the intersection of the first and second grooves. The non-magnetic material in the second groove is exposed in the sliding surface. The second groove has a width which is smaller than that of the first groove and is slightly larger than that of the main magnetic-pole film adjacent to its end exposed in the sliding surface, and a depth which is at least equal to that of the first groove. The magnetic member is exposed in the sliding surface in the vicinity of the main magnetic-pole film adjacent to its exposed end.

Thin-film perpendicular magnetic recording and reproducing head

A composite magnetic head is disclosed which is characterized by the fact that a magnetic head slider part and magnetic head core pieces both made of non-magnetic ceramic and provided on each of the opposed surfaces thereof with at least one layer of soft magnetic film produced in the form of sheet and subsequently shaped as required are integrally joined through the medium of glass members interposed between the opposed surfaces so as to give rise to a magnetic gap and an electromagnetic transducer coil is wound on the magnetic head core pieces. A composite magnetic head is further disclosed which is characterized by the fact that a magnetic head slider part and magnetic head core pieces, one made of an oxide magnetic material and the other made of a non-magnetic ceramic, are integrally joined through the medium of glass members interposed between pertinent opposed surfaces so as to give rise to a magnetic gap, the member made of the non-magnetic ceramic is provided on the opposed surface thereof with at least one layer of soft magnetic film produced in the form of sheet and subsequently shaped as required, and an electromagnetic transducer coil is wound on the magnetic head core pieces.

Composite magnetic head

A material for thin film magnetic head slider particularly suited for high recording, which is obtained by sintering a mixture consisting essentially of:

Material for magnetic head substrate member

A grooved magnetic substrate including an alumina film layer having a Knopp hardness of 600 kg/mm.sup.2 to 1200 kg/mm.sup.2 charged in at least one groove formed in a surface of a magnetic substrate. The magnetic substrate may be Mn-Zn or Ni--Zn base ferrite. The alumina film layer is formed by sputtering.

Grooved magnetic substrates and method for producing the same

Magnetic head sliders, materials therefor, and the process for the

A thin-film, perpendicular magnetic head includes a magnetic recording and reproducing substrate having a mechanochemically polished principal surface that includes a plurality of grooves filled with a nonmagnetic material; a thin-film conducting coil located on the polished surface of the substrate; an insulating layer of inorganic oxide covering the conductor coil and the polished principle surface of the magnetic substrate, this insulating layer including a via hole formed therein and having an exposed surface which is mechanochemically polished; a thin-film main pole on the polished surface of the insulating layer; and a protective overcoat covering the main pole.

Thin-film magnetic head

In a magnetic recording medium in which a metallic base layer and a magnetic layer are provided on a nonmagnetic nonmetallic substrate, an intermediate layer is additionally formed between the substrate and the metallic base layer in order to improve peeling-off resistance of the metallic base layer for durability against magnetic head contact-start-stop operation. The intermediate layer is a metal oxide layer including at least one of specified elements, or a composite layer made up of the metal oxide layer and a metal or alloy layer including at least one of the same specified elements and formed on the metal oxide layer. The specified element include Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and Mn. Oxygen concentration in the oxide layer may decrease toward the metallic base layer. The oxide layer may be replaced by nitride layer of these metals.

Magnetic recording medium

A process for producing a substrate member for magnetic recording disc with improved surface state free of defects such as micropores and strain due to machining, and improved surface roughness, such substrate being obtained by first forming a glass coating layer on the surface of a substrate of an alumina-based ceramic material containing therein micropores of 5 .mu.m or less and having a relative theoretical density of 90% or above; then, subjecting the glass coating layer on a substrate to the hot isostatic pressing treatment; and further subjecting the surface of the glass coating layer to mechanochemical polishing to a layer thickness in a range of from 3 .mu.m to 200 .mu.m and the surface free from micropores and strain. Glass coating may be done by glazing or vapor deposition like sputtering.

Process for producing substrate member for magnetic recording disc

A magnetic head slider and a material for it which comprises a sintered body obtained by sintering a raw material powder composed of 65 to 90% by weight of ZrO.sub.2 component containing therein a stabilizer and the balance of Al.sub.2 O.sub.3 component, 2% by weight or below of which has been substituted with a binder. The stabilizer is Y.sub.2 O.sub.3, MgO or CeO and the binder is Y.sub.2 O.sub.3 or MgO.

Magnetic head slider and material therefor

An improved magnetic recording disc comprising: a substrate member of an alumina-based ceramic material having micropores of 5 .mu.m or below and having a relative theoretical density of 90% or higher; a glass coating layer of a thickness of 3 to 200 .mu.m with a surface roughness (R.sub.z) of 180 angstroms or below, and being free from micropores and strain; a magnetic thin film formed on the surface of the glass coating layer; and a protective film formed thereon. A process for production of the magnetic recording disc comprises: forming a glass coating layer to a thickness of 5 to 220 .mu.m on the surface of an alumina-based ceramic substrate having micropores of 5 .mu.m or below and a relative theoretical density of at least 90%; then subjecting the glass coating layer to mechanochemical polishing to a layer thickness of 3 to 200 .mu.m, to make free from micropores and strain, and to have a surface roughness (R.sub.z) of 180 angstroms or below; and further coating the surface of the glass coating layer with a magnetic thin film and a protective film.

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Takatsuki, Japan

Toshiaki Wada