Showa Denko K.k.

Kabushiki Kaisha Toshiba

Other

Showa Denko Kabushiki Kaisha

Toshiba Corporation

Kenji Shimizu

Hiroshi Sakai

Akira Sakawaki

Soichi Oikawa

Takashi Hikosaka

Futoshi Nakamura

Takeshi Iwasaki

Tomoyuki Maeda

Hiro Mochizuki

Hui Yang

Kazuo Kobayashi

Masato Fukushima

Tsutomu Tanaka

Masakazu Kobayashi

Gohei Kurokawa

Haruhisa Ohashi

Yuka Aoyagi

Katsuaki Aida

Hideo Ogiwara

Ken Inoue

Masato Kokubu

Junichi Kishimoto

Akira Itoh

A method for manufacturing a magnetic recording medium is provided. An orientation control layer is deposited on a non-magnetic substrate to control an orientation of a layer located directly thereon, and a perpendicular magnetic layer whose easy axis of magnetization is mainly oriented perpendicular to the non-magnetic substrate is deposited thereon. In depositing the orientation control layer, a first granular structure layer containing Ru or a material mainly made of Ru and a first oxide having a melting point of 1000 degrees C. or lower are deposited by sputtering. In depositing the perpendicular magnetic layer, a second granular structure layer containing magnetic particles and a second oxide having a melting point of 1000 degrees C. or lower are deposited by sputtering, and the magnetic particles are grown so as to form a columnar crystal continuing in a thickness direction. The columnar crystal includes crystal grains constituting the orientation control layer.

Method for manufacturing magnetic recording medium, magnetic recording medium and magnetic recording and reproducing apparatus

The present invention has its object to offer magnetic recording medium and magnetic recording and reproducing device that can record and reproduce high density data by optimizing the soft magnetic layer material forming the soft magnetic underlayer and the under layer material. In the present invention, the perpendicular magnetic recording medium A has at least the soft magnetic underlayer a, the under layer, the intermediate layerand the perpendicular magnetic recording layer on the non-magnetic substrate. The soft magnetic layersthat form the soft magnetic underlayer a, has an amorphous structure and is made of CoAl alloy or CoFeAl alloy having saturation magnetic flux density Bs greater than 1.1 T.

Magnetic recording medium and magnetic recording and reproducing device

A magnetic recording medium A is provided on a non-magnetic substratewith at least a soft under layer &#x3b1;, an under film, an intermediate filmand a perpendicular magnetic recording film. The soft under layer a is a soft magnetic film having an amorphous structure. The under filmis formed of an Ni&#x2014;W alloy. The intermediate filmis formed of an Ru alloy. In the Ni&#x2014;W alloy, the Ni content is 80 atom % or more, and the W content is 20 atom % or less and preferably in the range of 1 atom % to 12 atom %. A magnetic recording and reproducing deviceequipped with the magnetic recording medium A is excellent in productivity and capable of recording and reproducing information of high density.

Magnetic recording medium and magnetic recording and reproducing device using the magnetic recording medium

A magnetic recording medium comprises a nonmagnetic substrate on which is disposed at least a vertical magnetic layer. The vertical magnetic layer comprises at least three layers including a lower layer, an intermediate layer and an upper layer from the substrate side. The lower, intermediate and upper magnetic layers are bound by ferro-coupling and are constituted of magnetic particles which are columnar crystals extending continuously from the lower layer to the upper layer. A nonmagnetic layer is between the lower and intermediate magnetic layers or between the intermediate and upper magnetic layers. The upper layer has a magnetic anisotropic constant (Ku) from 0.8&#xd7;10to 4&#xd7;10(erg/cc), the intermediate layer has a magnetic anisotropic constant (Ku) from 2&#xd7;10to 7&#xd7;10(erg/cc) and the lower layer has a magnetic anisotropic constant (Ku) from 1&#xd7;10to 4&#xd7;10(erg/cc).

A perpendicular magnetic recording medium includes: a substrate; at least one underlayer formed above the substrate; and a perpendicular magnetic recording layer formed above the at least one underlayer, an easy magnetization axis of the perpendicular magnetic recording layer being oriented perpendicular to the substrate, the perpendicular magnetic recording layer including magnetic crystal particles and grain boundaries surrounding the magnetic crystal particles, wherein the grain boundaries contain an oxide of silicon and at least one element selected from the group consisting of Li, Na, K, Rb, Cs, Ca, Sr, and Ba, and the ratio of a total amount of substance of Si, Li, Na, K, Rb, Cs, Ca, Sr, and Ba in the perpendicular magnetic recording layer is no less than 1 mol % and no more than 20 mol %.

Perpendicular magnetic recording medium, manufacturing method therefor, and magnetic read/write apparatus using the same

A magnetic-recording medium which is provided on a nonmagnetic substrate with at least an orientation-controlling layer for controlling the orientation of a layer formed directly thereon, a perpendicularly magnetic layer having an easily magnetizing axis oriented mainly perpendicularly relative to the nonmagnetic substrate, and a protective layer. The perpendicularly magnetic layer includes two or more magnetic layers, at least one of the magnetic layers is a layer having Co as a main component and containing Pt as well and containing an oxide, and at least another of the magnetic layers is a layer having Co as a main component and containing Cr as well and containing no oxide.

Magnetic recording medium, method for producing thereof, and magnetic recording and reproducing apparatus

A magnetic recording mediumwherein a substrate, undercoating layersandformed on the substrate, and a magnetic recording layer, which include the magnetic crystal grain and the grain boundary field which encloses magnetic crystal grains, are included. The grain boundary field includes Ti oxide, and the ratio of the substance amount of the Ti oxide in the magnetic recording layeris 5 mol % or more and 15 mol % or less, and the Ti oxide includes at least TiO and/or TiOs.

Magnetic recording medium, manufacturing method for the magnetic recording medium, and magnetic read/write apparatus

The invention provides a magnetic recording medium substrate product which enables enhancement of contact strength between a substrate end surface and a soft magnetic layer, as well as suppression of occurrence of corrosion, a magnetic recording medium including the substrate product, which exhibits no deterioration of electromagnetic conversion characteristics and has excellent durability and a magnetic recording and reproducing apparatus including the magnetic recording medium. The magnetic recording medium substrate product includes a disk-shaped non-magnetic substrate having a circular hole in a center portion thereof, and having a chamfer formed at least one of a portion between a main surface on which a magnetic layer is to be formed and an outer end surface and a portion between the main surface and an inner end surface defining the circular hole, wherein the chamfer has a surface roughness (Ra) falling within a range of 4.0 &#x212b;&#x2266;Ra&#x2266;100 &#x212b;, preferably 4.0 &#x212b;&#x2266;Ra&#x2266;50 &#x212b;, as measured by means of an AFM.

Substrate for magnetic recording medium, magnetic recording medium, and magnetic recording and reproducing apparatus

To make possible high density recording by making the structure of the perpendicular magnetic recording layer finer. A perpendicular magnetic recording mediumincludes at least a nonmagnetic under layer, a perpendicular magnetic layer, and a protective layer which are stacked on a nonmagnetic substrate, wherein the perpendicular magnetic layer includes ferromagnetic crystal grains and nonmagnetic crystal grain boundary regions, wherein the crystal grain boundary region includes at least two kinds of oxide.

Perpendicular magnetic recording medium and magnetic recording/reproducing apparatus

A magnetic recording medium which is provided on a nonmagnetic substratewith at least an orientation-controlling layerfor controlling the orientation of a layer formed directly thereon, a perpendicularly magnetic layerhaving an easily magnetizing axis oriented mainly perpendicularly relative to the nonmagnetic substrate, and a protective layerand characterized in that the perpendicularly magnetic layerincludes two or more magnetic layers, that at least one of the magnetic layers is a layerhaving Co as a main component and containing Pt as well and containing an oxide and that at least another of the magnetic layers is a layerhaving Co as a main component and containing Cr as well and containing no oxide.

Magnetic recording medium, production process thereof, and magnetic recording and reproducing apparatus including both oxide and non-oxide perpendicular magnetic layers

Disclosed is a magnetic recording medium which includes a substrate, an underlayer, and a perpendicular magnetic recording layer, and in which this perpendicular magnetic recording layer contains magnetic crystal grains and a matrix surrounding the magnetic crystal grains, and the matrix contains an element selected from Zn, Cd, Al, Ga, and In, and a component selected from P, As, Sb, S, Se, and Te.

Perpendicular magnetic recording medium, method for manufacturing the same, and magnetic recording/reproducing apparatus

An orientation control layer having a granular structure is formed between a substrate and magnetic recording layer, contains a base material and grains dispersed in the base material, and having a thickness smaller than a grain size of the grains.

Magnetic recording medium and magnetic recording/reproducing apparatus

A multi-layer including a magnetic recording layer and a high-magnetostriction layer having a magnetostriction constant larger than that of the magnetic recording layer is formed.

Magnetic recording medium including a high-magnetostriction layer and magnetic recording/reproducing apparatus

A magnetic recording medium, a method for producing the same, and a magnetic recording and reproducing device are provided which can prevent spike noise and improve the error rate. The magnetic recording medium comprises at least one nonmagnetic substrate, a soft magnetic underlayer, an orientation control layer to control the orientation of the layer formed directly above the same, and a perpendicular magnetic layer having an axis of easy magnetization which is oriented mainly perpendicularly to the nonmagnetic substrate. The soft magnetic underlayer is formed with a multilayer structure having at least two soft magnetic layers and one or more separation layers interposed between the soft magnetic layers, and at least one of the soft magnetic layers comprises a material with a structure having no magnetic domain walls.

Magnetic recording medium utilizing a multi-layered soft magnetic underlayer, method of producing the same and magnetic recording and reproducing device

A magnetic recording medium includes a nonmagnetic substrate on which is provided at least a soft magnetic under-film, an orientation control film that controls an orientation of a film directly above, a perpendicular magnetic recording film having an axis of easy magnetization oriented to be mainly perpendicular to the substrate and a protective film, wherein the orientation control film is alloy containing at least Cr and C. The magnetic recording medium is manufactured by a method including carrying out, in order, at least a step of forming a soft magnetic under-film on a nonmagnetic substrate, a step of forming an orientation control film that controls an orientation of a film directly above, a step of forming a perpendicular magnetic recording film having an axis of easy magnetization oriented to be mainly perpendicular to the substrate, and a step of forming a protective film. A magnetic recording and reproduction apparatus includes the magnetic recording medium and a magnetic head that records and reproduces information on the magnetic recording medium, wherein the magnetic head is a magnetic monopole head.

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Ichihara, Japan

Kenji Shimizu