Hitachi, Ltd.

Hitachi Global Storage Technologies Japan, Ltd.

Hitachi Global Storage Technologies Netherlands B.v.

Shiseido Company, Limited

Hitachi Storage Technologies Japan, Ltd.

Tetsuya Kanbe

Yuzuru Hosoe

Kiwamu Tanahashi

Yotsuo Yahisa

Ichiro Tamai

Tomoo Yamamoto

Yoshio Takahashi

Akira Ishikawa

Yoshibumi Matsuda

Koji Sakamoto

Satoshi Matsunuma

Hiroyuki Suzuki

Hidekazu Kashiwase

Tatsuya Hinoue

Hiroyuki Kataoka

Fumiyoshi Kirino

Toshinori Ono

Nagatugu Koiso

Shinji Fukaya

Naoto Endo

Yoshifumi Matsuda

Kazuhiro Ura

Yoshihiro Shiroishi

Yoshiyuki Hirayama

Jo Inagaki

Masukazu Igarashi

Kai Tang

Hiroshi Tanaka

Takashi Matsumoto

Xiaoping Bian

Mary Frances Doerner

Mohammad Taghi Mirzamaani

Tomiyuki Nanba

Toshiaki Kobayashi

Masaaki Ishiwatari

Toshio Yoneyama

Yoshiyuki Ogusu

Adam Polcyn

Mark F Mercado

Kimio Ohno

Takashi Isa

Embodiments of the present invention provide a magnetic recording medium for use in high-reliable magnetic recording apparatus capable of reading/writing information with high density. In one embodiment, a magnetic recording apparatus includes a magnetic recording medium, a driver for driving the medium in a recording direction, a compound type magnetic head having an electromagnetic induction type magnetic head for recording and a spin-valve type magnetic head for reading in combination, a mechanism to move the head relative to the medium, and a read/write signal processing module for the head. The magnetic recording medium has a magnetic layer formed by way of a first underlayer, a second underlayer and a third underlayer on a substrate. The first underlayer comprises an alloy of an amorphous structure, the second underlayer comprises a W element or a W-containing alloy layer, the third underlayer comprises one or more Cr-based alloy layers of a body-centered cubic structure, and the magnetic layer comprises one or more Co-based alloy layers of a hexagonal close-packed structure.

Magnetic recording medium

An antiferromagnetically coupled (AFC) magnetic recording medium with an AFC master layer comprising at least two magnetic layers with the top magnetic layer including copper is described. The slave layer is separated from the master layer structure by a nonmagnetic spacer layer selected to antiferromagnetically couple the layers. The master layer structure according to the invention includes a bottom and top layer of distinct ferromagnetic materials. Preferably, the top layer of the master layer is a cobalt alloy including from 1 to 5 at. % copper with an example being CoPtCrBCu. The AFC magnetic layer structure can be used with a variety of substrates including circumferentially textured glass and NiP/AlMg.

Magnetic recording disk with antiferromagnetically coupled master layer including copper

An inplane magnetic recording medium having high S/N and thermal stability and a reliable magnetic storage device having surface recording density of 50 megabit/mmor more is described. The magnetic recording medium includes magnetic layers formed on a nonmagnetic substrate with a plurality of ground layers therebetween, at least one of the ground layers formed from an alloy of a body-centered cubic structure containing Cr as a main component and B of from 2 atomic % to 12 atomic %. Main components of the magnetic layers include a lower magnetic layer containing Co and Cr of from 10 atomic % to 16 atomic %, with film thickness of from 1.5 nm to 4.5 nm, and an upper magnetic layer containing Co, coupling anti-ferromagnetically with the lower magnetic layer through nonmagnetic intermediate layers.

Magnetic recording medium and magnetic storage device

A magnetic recording medium capable of attaining high in-plane recording density of 100 Mbits or more per 1 mmis provided. Magnetic recording medium is provided in which underlayers, a first magnetic layer, a first intermediate layer, a second magnetic layer, a second intermediate layer, a third magnetic layer, a protection layer and lubrication layer are formed in this order above a substrate. Each of the third magnetic layer and the second magnetic layer comprises a Co-based alloy containing at least Pt, Cr and B. The concentration of Pt contained in the second magnetic layer is not more than that in the third magnetic layer.

Longitudinal multi-layer magnetic recording medium

A magnetic recording apparatus including a drive unit to drive the magnetic recording medium, a compound-type magnetic head, a means to move the magnetic head relative to the magnetic recording medium, and a means to process recording and retrieving signals generated by the magnetic head. The magnetic recording medium comprises a non-magnetic substrate and a magnetic layer formed thereon with three underlayers interposed inbetween. The magnetic layer is composed of a plurality of layers of Co-based alloy of hexagonal close-packed structure which are antiferromagnetically coupled to one another through a non-magnetic intermediate layer, said three underlayers including an amorphous alloy layer, a Ta layer, and a Cr-based alloy layer of body-centered cubic structure.

Magnetic recording medium and magnetic recording apparatus

A magnetic recording medium having at least two magnetic layers and a non-magnetic intermediate layer held between them. The first magnetic layer (which is closer to the substrate than the non-magnetic intermediate layer) is formed from an alloy composed of Co, Pr, and Cr, with Pt content being 3-9 at %. The second magnetic layer (which is farther from the substrate than the non-magnetic intermediate layer) is formed from a Co-based alloy containing Pt, Cr, and B. The first and second magnetic layers are magnetized in the mutually antiparallel direction in the absence of an applied magnetic field. The magnetic recording medium is characterized by good thermal stability for recording bits, high recording resolution, and low media noise. It is suitable for a magnetic storage for high recording density with high reliability.

Magnetic recording medium and magnetic recording system using the same

A large-capacity, low-cost, longitudinal magnetic recording medium capable of ultra-high-density recording of 70 Gigabits or more per square inch is disclosed. The longitudinal magnetic recording medium of the present invention comprises a first seed layer, a second seed layer, a first underlayer, a second underlayer, and a magnetic layer, which are formed on a nonmagnetic substrate in this order. A material containing at least Al and any one of Ru and Re is used to form the second seed layer, and a material containing at least any one of Co and Ni and one or both of Al and Ti is used to form the first underlayer. It is also possible to use Cr or a Cr alloy containing Cr and at least one element selected from the constituent element group A consisting of Ti, Mo, and W for forming the second seed layer.

A magnetic recording system includes an in-plane magnetic recording medium having a magnetic layer fabricated on a single underlayer or on a plurality of underlayers respectively fabricated on a substrate; a driver unit for driving the in-plane magnetic recording medium in a write direction; a magnetic head having a read unit and a write unit; a unit for moving the magnetic head relative to the in-plane magnetic recording medium; and a read/write signal processing unit for reading an output signal from the magnetic head and writing an input signal to the magnetic recording media, wherein the read unit of the magnetic head is a magnetoresistive head and the single underlayer or at least one of the plurality of underlayers is made of Co-containing amorphous material or fine crystal material, or is made of alloy material, the alloy material having as the main components at least one element selected from a group consisting of Cr, Mo, V and Ta and containing at least one element selected from a group consisting of B, C, P and Bi. The magnetic recording system can be realized which can read and write high density information and have high reliability.

Magnetic recording media and magnetic recording system using the same

In a magnetic storage apparatus having a magnetic recording medium, a drive unit for driving this medium in a prespecified recording direction, a magnetic head assembly including a recorder section and reproduction section, means for causing the magnetic head to move relatively with respect to the magnetic record medium, and a record/playback signal processor means for performing signal inputting to the magnetic head and for effecting reproduction of an output signal from the magnetic head, the reproduction section of said magnetic head is composed of a magnetic head of the magnetoresistance effect type, while said magnetic record medium is structured including a substrate and a magnetic layer formed thereover with one or several underlayers being sandwiched therebetween, wherein at least one of the underlayers is a specific layer that is made of amorphous or microcrystalline materials containing therein Ni as the principal or main component thereof and further containing at least one kind of element as selected from the group consisting of Nb and Ta.

Magnetic recording media and magnetic storage apparatus using the same

The longitudinal magnetic recording medium includes a non-magnetic substrate, a first underlayer having at least one of an amorphous structure and a fine crystal structure formed on the non-magnetic substrate, a second underlayer having a body-centered cubic structure formed on the first underlayer, a third underlayer having a hexagonal closed packed structure formed on the second underlayer, and a magnetic layer having the hexagonal closed packed structure formed on the third underlayer, wherein the third underlayer is composed of an alloy containing Co and Ru.

A magnetic storage device has a magnetic layer, the magnetic crystal grains of which are separated by a nonmagnetic phase. The typical crystal grain is in the approximate shape of a sphere or an ellipsoid. The thickness of the magnetic crystal grains, which is in the direction perpendicular to the surface or the film, is smaller than that of the thickness of the magnetic film. The ratio of the coercive force, which is measured in the circumferential direction, to the coercive force, which is measured in the radial direction, (the orientation ratio of the coercive force), is larger than 1.0, but preferably nor greater than 3.0. Further, the area fraction of the magnetic grains having an extended axis within 30&#xb0; from the circumferential direction is equal to or more than 45%.

Magnetic recording medium and a magnetic storage apparatus

It is an object of the present invention to provide a high reliability magnetic storage apparatus capable of performing writing and reading back of high density information. The magnetic storage apparatus is so configured as to have a longitudinal magnetic recording medium including: a magnetic layer formed on a non-magnetic substrate via a plurality of underlayers; the magnetic layer including a lower magnetic layer containing Ru in an amount of not less than 3 at % to not more than 30 at %, and Cr in an amount of not less than 0 at % to not more than 18 at %, and further containing at least one of B or C in an amount of not less than 0 at % to not more than 20 at %, and an upper magnetic layer containing Co as a main component disposed thereon via a non-magnetic intermediate layer.

A magnetic recording medium includes a first underlying film of a NiTa alloy having a nonmagnetic amorphous structure and formed on a nonmagnetic substrate, and a second underlying film made of an alloy containing Cr and Ti, further a first magnetic film of a CoCrPt alloy, a nonmagnetic intermediate film of Ru and a second magnetic film of a CoCrPtB alloy that are serially formed over the first underlying film, wherein oxygen locally exists in an interface between the first underlying film and the second underlying film.

Magnetic recording medium and manufacturing method thereof

A magnetic recording medium having first undercoating layers &prime; formed directly or via substrate face undercoating layers on a substrate , second undercoating layers &prime; directly formed on the first undercoating layers &prime;, magnetic films &prime; formed on the second undercoating layers &prime;, and protective films &prime; formed on the magnetic films &prime;. Clusters having a large amount of oxygen are dispersed on the boundary face of the first and second undercoating layers. Preferably, the first undercoating layer is made of an alloy which includes two kinds of elements in which the difference between oxide formation standard free energies &Dgr;G&deg; of the elements at the temperature of 250&deg; C. is large.

Magnetic recording medium, method of fabricating magnetic recording medium, and magnetic storage

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Odawara, Japan

Tetsuya Kanbe