Kabushiki Kaisha Toshiba

Showa Denko K.k.

Other

Futoshi Nakamura

Hiroshi Sakai

Soichi Oikawa

Kenji Shimizu

Takashi Hikosaka

Akira Sakawaki

Takeshi Iwasaki

Tomoyuki Maeda

Hideo Ogiwara

Kazuo Kobayashi

Akira Kikitsu

Katsutaro Ichihara

Yoichiro Tanaka

Keiichiro Yusu

Hiro Mochizuki

Hui Yang

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

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.

Magnetic recording medium, method of manufacturing the same, and magnetic recording and reproduction apparatus

Disclosed is a perpendicular magnetic recording medium in which an undercoating layer having crystal grains and a grain boundary material containing a carbide or boride is formed below a perpendicular magnetic recording layer, and another undercoating layer containing one of elements forming the crystal grains is formed below the aforementioned undercoating layer, and which can perform high&#x25a1;density recording by further decreasing the grain size of the perpendicular magnetic recording layer.

A perpendicular magnetic recording medium includes a magnetic recording layer stacked on a substrate and having a first perpendicular magnetic recording layer containing cobalt, and a second perpendicular magnetic recording layer mainly containing a crystalline alloy which contains a rare earth element and a transition metal.

Perpendicular magnetic recording medium and magnetic recording/reproduction apparatus

In a magnetic recording medium, a longitudinal hard magnetic layer, interlayer, longitudinal soft magnetic layer, and magnetic recording layer are multilayered on a substrate. The interlayer is one of a magnetic layer having saturation magnetization smaller than that of the longitudinal hard magnetic layer, a nonmagnetic layer mainly containing cobalt or ruthenium or having a thickness of 0.5 nm or less, and an oxide layer of the longitudinal hard magnetic layer.

Perpendicular magnetic recording medium and magnetic recording/reproducing apparatus using the same

A double layered perpendicular recording media having, between a soft magnetic layer and perpendicular magnetic recording layer, an alignment control layer containing an amorphous portion, a crystal size control layer, and an underlayer having one of a hexagonal closest packed structure and a face-centered cubic structure.

Perpendicular magnetic recording medium and magnetic recording apparatus

Disclosed is a perpendicular magnetic recording medium, comprising a nonmagnetic substrate, a longitudinal hard magnetic multi-layered film arranged on the nonmagnetic substrate, including a nonmagnetic intermediate layer and a pair of hard magnetic layers laminated one upon the other with the nonmagnetic intermediate layer interposed therebetween, and having at least two hard magnetic layers, a longitudinal soft magnetic layer formed on the longitudinal hard magnetic multi-layered film, and a perpendicular magnetic recording layer formed on the longitudinal soft magnetic layer. The perpendicular magnetic recording medium of the particular construction is capable of suppressing noise and achieves a high recording magnetic field intensity and a high recording resolution.

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Ichikawa, Japan

Futoshi Nakamura