Hoya Corporation

Konica Corporation

Mitsubishi Kasei Corporation

Doryokuro Kakunenryo Kaihatsu Jigyodan

Hoya Magnetics Singapore Pte. Ltd.

Wd Media (singapore) Pte. Ltd.

Other

Mitsubishi Chemical Corporation

Konishiroku Photo Industry Co., Ltd.

Mitsubishi Chemical Industries Limited

Hiroshi Tomiyasu

Teiichiro Umezawa

Tomotaka Yokoyama

Kiyoshi Goto

Takashi Morikawa

Genshichi Hata

Takemi Miyamoto

Kouji Takahashi

Yukio Wada

Hideyuki Nakai

Takayuki Goibuchi

Kyoichi Morimoto

Masato Kobayashi

Masafumi Ishiyama

Akeo Kasakura

Kenji Ayama

Nobuyuki Eto

Norihito Suzuki

Tsuyoshi Watanabe

Masatomo Shibui

Keiji Moroishi

Kazuo Noguchi

Masashi Suzuki

Satoshi Yokota

Yoshiko Kobayashi

Takeshi Yamamoto

Shinichi Matsubara

Junichi Horikawa

Nobumasa Sasa

Koichi Shimokawa

Kota Suzuki

Kaori Fukumuro

Shigeo Tsuji

Tetsuya Taniguchi

Kimi Ojima

Yoshihiro Maeda

Yoshiko Fujita

Shigeru Kajiwara

Yoshihiro Koya

In a magnetic disk including a magnetic layer, a protecting layer and a lubricating layer on a substrate, the lubricating layer is formed by a self assembly monolayer. A material of the self assembly monolayer is a hydrocarbon-based silane agent or a partial fluorinated hydrocarbon-based silane agent. The magnetic layer and the protecting layer (P) are sequentially formed on the substrate, and then the substrate on which the magnetic layer and the protecting layer (P) are formed is immersed in a solution containing the hydrocarbon-based silane agent or the partial fluorinated hydrocarbon-based silane agent, and thus a lubricating layer (L) is formed on the protecting layer (P).

Magnetic disk and method of manufacturing the same

Disclosed is a magnetic disk which has a lubricant layer with excellent heat resistance and high adhesiveness and is free from fly-stiction failure or corrosion failure even at an extremely low flying height of 10 nm or lower. Also disclosed is a magnetic disk which has a lubricant layer with good thermal properties and can exert a stable action over a wide temperature range. The magnetic disk comprises a substrate (), and a magnetic layer (), a carbon-containing protective layer () and a lubricant layer () provided on the substrate (), wherein the lubricant layer () contains a magnetic disk lubricant comprising a compound having a phosphazene ring and two or more hydroxyl and/or carboxyl groups in the molecule.

Magnetic disk

There is disclosed a magnetic recording medium in which a seed layer, under layer, intermediate layer, first magnetic layer, nonmagnetic layer, second magnetic layer, protective layer, and lubricant layer are successively laminated on a glass substrate, the nonmagnetic layer is constituted of an alloy containing Cr and C, and the magnetic layer is constituted of an alloy containing Co and Pt. The under layer includes at least the seed layer for finely dividing the crystal particles of the magnetic layer, the seed layer includes at least two or more layers of nonmagnetic films, and the intermediate layer formed of the material different from that of the nonmagnetic film is interposed between the nonmagnetic films. In measurement of the thermal stability of the magnetic recording medium, a head is used, the head includes a read/write element, and a write track width is twice or more as large as a read track width in the head.

Magnetic recording medium, and thermal stability measuring method and apparatus of magnetic recording medium

There are disclosed an information recording medium substrate having a surface roughness of Rmax 15 nm or less, and an information recording medium, particularly an information recording medium substrate and information recording medium in which for surfaces of the substrate and medium, a bearing area value (offset bearing area value) in a depth of 0.5 to 5 nm (predetermined slice level) from a bearing height (real peak height) corresponding to the bearing area value of 0.2% to 1.0% is 90% or less, and a manufacture method of the substrate and medium.

Management technique of friction coefficient based on surface roughness, substrate for information recording medium, information recording medium and manufacture method thereof

In a magnetic recording medium which comprises a substrate (), a magnetic layer () formed on the substrate, a carbon-based protection layer () comprising carbon and formed on the magnetic layer, and a lubrication layer () formed on the carbon-based protection layer, the carbon-based protection layer comprises a hydrogenated carbon protection layer () facing the magnetic layer and a nitrogenated carbon protection layer () facing the lubrication layer. The hydrogenated carbon protection layer () comprises carbon and hydrogen. The nitrogenated carbon protection layer () includes no hydrogen but comprises carbon and nitrogen.

Magnetic recording medium with multi-portion carbon-based protection layer, and apparatus thereof

Magnetic recording medium

In a magnetic disk having a glass substrate, an amorphous underlayer is formed on the glass substrate. A magnetic layer is formed on the amorphous underlayer. The glass substrate is provided with a texture formed to induce magnetic anisotropy in the magnetic layer. The amorphous underlayer contains a group IVa element on a glass substrate side and a group Va element on a magnetic layer side.

Magnetic disk using a glass substrate

A substrate for an information recording medium has a microwaviness average height Ra' not greater than 0.05 microinch as measured by a contactless laser interference technique for measurement points within a measurement region of 50 &#x3bc;m&#x25a1;-4 mm&#x25a1; on a surface of the substrate. The microwaviness average height Ra&#x2032; is given by:where xi represents a measurement point value of each measurement point, {overscore (x)} representing an average value of the measurement point values, n representing the number of said measurement points. Alternatively, the substrate has a waviness period between 300 &#x3bc;m and 5 mm and a waviness average height Wa of 1.0 nm or less as measured by the contactless laser interference technique for measurement points in a measurement region surrounded by two concentric circles which is spaced from a center of a surface of the substrate by a predetermined distance. The waviness average height Wa is given by:where Xi represents a measurement point value of each measurement point, {overscore (X)} representing an average value of the measurement point values, n representing the number of said measurement points.

Substrate for an information recording medium, information recording medium using the substrate, and method of producing the substrate

A substrate for an information recording medium, wherein the period of microwaviness is 2 &mgr;m to 4 mm, and if we let wa be the maximum height of this microwaviness and Rmax be the maximum height measured by atomic force microscope, the main surface of the substrate has a wa of no more than 5 nm and an Rmax of no more than 12 nm, provided that wa is the difference between the highest and lowest points on a measurement curve of all measured points in a measurement area.

Substrate for information recording medium, information recording medium, and method for controlling surface of substrate for information recording medium

In a magnetic recording medium which includes a base body ( - ), first and second magnetic layers ( and ), each being of a ferromagnetic material, and a spacer layer ( ) formed between the first and the second magnetic layers for inducing antiferromagnetic exchange interaction between the first and the second magnetic layers, the second magnetic layer located farther from the base body than the first magnetic layer includes a primary layer ( ) and a secondary layer ( ) located nearer to the base body than the primary layer. The primary layer has a primary anisotropic magnetic field while the secondary layer has a secondary anisotropic magnetic field which is smaller than the primary anisotropic magnetic field. The first magnetic layer is for controlling the antiferromagnetic exchange interaction.

Antiferromagnetically coupled magnetic recording medium with dual-layered upper magnetic layer

A magnetic recording medium that is high coersive force, hard to receive influence of thermal fluctuation, and brings about a considerable improvement of S/N ratio, and in which at least an underlayer and a magnetic layer are sequentially laminated on a substrate, wherein a pre-coat layer is interposed between said underlayer and said substrate and said pre-coat layer is constructed by sequentially laminating a lower layer containing Ni and P and an upper layer made of a Cr alloy.

Magnetic recording medium and manufacturing method therefor

Substrate for an information recording medium, information recording medium using the substrate and method of producing the substrate

An unsaturated group-containing urethane compound of the following formula (I): ##STR1## wherein X is a C.sub.1-20 alkylene group which may be branched, and R.sup.1 is a group of the following structural formula (A) or (B): ##STR2## wherein each of R.sup.2 and R.sup.3 which are independent of each other, is a hydrogen atom or a methyl group, and Y is a C.sub.1-6 alkylene group which may be branched.

Unsaturated group-containing urethane compound, photopolymerizable

Growing community of inventors

Tokyo, Japan

Hiroshi Tomiyasu