Wd Media (singapore) Pte. Ltd.

Hoya Corporation

Wd Media, LLC

Kong Kim

Yoshiaki Sonobe

Teiichiro Umezawa

Junichi Horikawa

Satoshi Ishii

Kinobu Osakabe

Takahiro Onoue

Masafumi Ishiyama

Kenji Ayama

Kazuaki Sakamoto

Masaki Uemura

Hi Shin

Tomoko Seki

A perpendicular magnetic recording medium includes a substrate, a soft magnetic layer, a pre-underlayer, an underlayer, and a main recording layer serving as a magnetic recording layer. The pre-underlayer contains seed crystal grains that serve as a base for crystal grains of the underlayer, and an addition substance that is added between the seed crystal grains and composed of an element having an atomic radius smaller than that of an element forming the seed crystal grains.

Perpendicular magnetic recording medium and method of manufacturing the same

A perpendicular magnetic recording medium is disclosed that includes a substrate, a main recording layer, a reinforcing layer, and a continuous layer which are overlaid in this order on the substrate. The reinforcing layer is provided between the main recording layer and the continuous layer so as to improve the S/N ratio of the magnetic recording medium and reduce the write fringing effect. The reinforcing layer has a granular structure. The saturation magnetization Ms of the reinforcing layer is higher than the saturation magnetization of the main recording layer.

Perpendicular magnetic recording medium and perpendicular magnetic recording medium manufacturing method

A perpendicular magnetic recording medium is used for information recording of a perpendicular magnetic recording type. The perpendicular magnetic recording medium includes a substrate, a soft magnetic layer, an underlayer, and a magnetic layer having a multilayered structure including a plurality of magnetic layers. The soft magnetic layer, the underlayer, and the magnetic layer are formed on the substrate. At least one of the magnetic layers includes CoPt magnetic grains containing oxide. The oxide includes at least one material selected from the group consisting of SiO, TiO, CrO, TaO, WO, CoO, and CoO.

Perpendicular magnetic recording medium

[PROBLEMS] To provide a process for producing a magnetic recording medium, which can simultaneously realize increased high recording density, high impact resistance, and prevention of corrosion, by providing an underlayer which, even when formed at a low gas pressure, can exhibit a high level of coercive force. [MEANS FOR SOLVING PROBLEMS] A process for producing a perpendicular magnetic recording medium, comprising the step of forming a nonmagnetic underlayer () having a granular structure, in which crystal particles are grown in a column form, on a substrate, and forming a magnetic recording layer () having a granular structure in which magnetic particles are grown in a column form. The process is characterized in that the underlayer () is any one of CoCr or CoCrX (wherein X is a nonmagnetic material), CoCr-oxide, and CoCrX-oxide, and the film forming gas pressure of the underlayer () is not more than 4 Pa.

Method of manufacturing a perpendicular magnetic recording medium

A magnetic diskfor use in perpendicular magnetic recording, which includes an underlayer, a size-reduction promoting layer(nonmagnetic granular layer) of a granular structure, and a magnetic recording layerhaving a ferromagnetic layerof a granular structure. The size-reduction promoting layerhas an inorganic oxide matrix and nonmagnetic metal crystal grains and is disposed between the underlayerand the ferromagnetic layer, thereby reducing the size of magnetic crystal grains in the ferromagnetic layer

Perpendicular magnetic recording disk and manufacturing method thereof

In a perpendicular magnetic recording medium which includes a substrate () of a nonmagnetic material, first and second nonmagnetic underlayers (and) formed on the substrate, and a perpendicular magnetic recording layer () formed on the first and the second nonmagnetic underlayers, the first nonmagnetic underlayer is made of an amorphous nonmagnetic metal material containing a metal element which forms a face-centered cubic (fcc) crystal structure by a simple substance. The second nonmagnetic underlayer is formed on the first nonmagnetic underlayer in contact with the first nonmagnetic underlayer and made of a nonmagnetic material containing a hexagonal close packed structure. The perpendicular magnetic recording layer is formed on the second nonmagnetic underlayer in contact with the second nonmagnetic layer.

A perpendicular magnetic recording medium comprising a pair of soft magnetic layers that are laminated via a non-magnetic layer and antiparallel-coupled to each other and that are provided between a non-magnetic substrate and a magnetic recording layer, wherein spike noise and medium noise can be positively suppressed when information recording and reproduction are carried out at high recording surface density. At least one pair of soft magnetic layers are laid and formed via a non-magnetic layer on a substrate of a non-magnetic material so that magnetic characteristics obtained by integrating the pair of soft magnetic layers have a magnetic hysteresis to thereby prevent the formation of a magnetic domain wall.

Magnetic recording medium substrate and perpendicular magnetic recording medium

A disk substrate for a perpendicular magnetic recording medium comprises a disk base member, a soft magnetic layer formed on the disk base member, and a protection layer formed on the soft magnetic layer. The soft magnetic layer and the protection layer are deposited by sputtering. A perpendicular magnetic recording disk comprises the above-mentioned disk substrate and at least a perpendicular magnetic recording layer formed thereon. The perpendicular magnetic recording layer is deposited on the disk substrate by sputtering after the disk substrate is heated.

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Tokyo, Japan

Kong Kim