Hitachi, Ltd.

Hitachi Global Storage Technologies Netherlands B.v.

Hgst Netherlands, B.v.

Hitachi Global Storage Technologies Japan, Ltd.

Reiko Arai

Susumu Soeya

Kiwamu Tanahashi

Masaaki Sano

Katsuya Mitsuoka

Hiroshi Fukui

Hiroyuki Hoshiya

Moriaki Fuyama

Fumio Sato

Katsuro Watanabe

Yuzuru Hosoe

Hiromasa Takahashi

Atsushi Kikugawa

Yoshiyuki Hirayama

Yoshiaki Kawato

Masayoshi Shimizu

Hiroyuki Matsumoto

Ichiro Tamai

Yoshinori Honda

Hiroyuki Nakagawa

Ikuko Takekuma

Yoko Ogawa

Tomio Iwasaki

Hiroyuki Suzuki

Yutaka Sugita

Masaaki Hayashi

Takehiko Hamaguchi

Mikio Suzuki

Takao Imagawa

Shinji Narishige

Katsumi Mabuchi

Tetsuo Kobayashi

Hideaki Maeda

Kouichi Nishioka

Yokuo Saitoh

Mitsuhiro Shoda

Mineaki Kodama

Shun Tonooka

Toshihiro Yoshida

Akira Kumagai

Yoshikazu Tsuji

Niroyuki Nakagawa

Liping Shen

A medium having high medium S/N and excellent corrosion resistance is achieved. In one embodiment, an adhesion layer, a soft magnetic layer, an intermediate layer, a magnetic recording layer, and a protective layer are deposited, in order, on a substrate. The soft magnetic underlayer consists at least of two soft magnetic layers, the first soft magnetic layer formed on the recording layer side being composed of an amorphous alloy containing 85 at. % or less of Co, and the second soft magnetic layer formed on the substrate side being composed of an alloy containing more than 85 at. % of Co.

Perpendicular magnetic recording medium with high medium S/N

According to one embodiment, a PMRM includes a substrate, a soft magnetic underlayer above the substrate, an underlayer above the soft magnetic underlayer, an oxide-containing magnetic layer above the underlayer, and a ferromagnetic layer above the magnetic layer having no oxides. The underlayer controls orientation and segregation of the magnetic layer. The oxide-containing magnetic layer comprises at least two or more magnetic layers, a Cr concentration of the magnetic layer adjacent to the ferromagnetic metal layer is between about 23 at. % and about 32 at. %, and a difference between the Cr concentration of the magnetic layer adjacent to the ferromagnetic metal layer and a magnetic layer having a lowest Cr concentration among the at least three magnetic layers is less than about 25 at. %, the magnetic layer with a lowest Cr concentration has a granular structure, and a nucleation field is greater than about 159.2 kA/m.

Perpendicular magnetic recording medium (PMRM) and magnetic storage device using the same

According to one embodiment, a perpendicular magnetic recording medium includes a soft magnetic underlayer having an amorphous structure or a microcrystalline structure, a first seed layer comprised of a magnetic material having an fcc crystal structure including a CoFe alloy formed on a substrate side, and a second seed layer formed on the first seed layer, the second seed layer comprised of a nonmagnetic material having an fcc crystal structure including a NiW alloy. The medium also includes an intermediate layer comprised of Ru or an alloy thereof, a magnetic recording layer, and a protective layer, wherein the layers are sequentially stacked on a substrate in the foregoing order and the protective layer is closer to the substrate than the soft magnetic underlayer. Other embodiments of magnetic recording media, and methods of fabrication, are also described.

Perpendicular magnetic recording medium

According to one embodiment, a perpendicular magnetic recording medium includes at least one soft magnetic underlayer above a substrate, a seed layer above the at least one soft magnetic underlayer, an intermediate layer above the seed layer, a magnetic recording layer above the intermediate layer, and an overcoat layer above the magnetic recording layer, wherein the seed layer includes a second seed layer above a first seed layer. In another embodiment, the seed layer is a multilayered structure of at least two cycles of a unit of layered film which includes a first seed layer and a second seed layer. The first seed layer includes a non-magnetic alloy having a Face-Centered-Cubic (FCC) structure, and the second seed layer includes a soft magnetic alloy having a FCC structure. Other structures are also disclosed, according to more embodiments.

Perpendicular magnetic recording medium having FCC seed layers

Embodiments of the present invention provide a perpendicular magnetic recording medium which does not cause medium noise to increase due to soft magnetic underlayers, is capable of easily controlling the thickness of a nonmagnetic layer disposed between soft magnetic underlayers, and capable of improving the corrosion resistance of the soft magnetic underlayers. According to one embodiment, in a perpendicular magnetic recording medium, an adhesion layer is formed on a substrate, a soft magnetic underlayer is formed on the adhesion layer, a seed layer and an intermediate layer are formed above the soft magnetic underlayer, and a perpendicular layer is formed on the intermediate layer. The soft magnetic underlayer has a first soft magnetic layer, a second first soft magnetic layer, and an antiferromagnetic coupling layer disposed between the first soft magnetic layer and the second soft magnetic layer, the first soft magnetic layer and the second soft magnetic layer are formed of an alloy comprising Fe as a main ingredient, the antiferromagnetic coupling layer is formed of an Ru&#x2014;Fe alloy, and an Fe content is from 40 at % to 75 at %.

Embodiments in accordance with the present invention help to obtain a perpendicular magnetic recording medium having a granular structure, excellent recording/reproducing properties, and excellent durability. According to one embodiment, a recording layer includes a layer which has crystal grains mainly composed of cobalt and crystal grain boundaries mainly composed of the oxide; the oxygen content of the recoding layer is changed in the film thickness direction; the oxygen content in the area in the vicinity of the interface between the recording layer and the intermediate layer is made lower than the oxygen content in the area in the vicinity of the center of the recording layer; and the oxygen content in the area in the vicinity of the interface between the recording layer and the protective layer is made lower than the oxygen content in the area in the vicinity of the center of the recording layer.

Perpendicular magnetic recording medium and magnetic storage apparatus using the same

Embodiments of the invention provide a perpendicular magnetic recording medium improved for fly ability, high in read signal quality, and capable of suppressing magnetic decay of recorded magnetization to be caused by stray fields. In one embodiment, a perpendicular recording layer is formed over a substrate with a soft magnetic underlayer therebetween, then an amorphous or nano-crystalline layer is formed between the substrate and the soft magnetic underlayer. The soft magnetic underlayer includes first and second amorphous soft magnetic layers, as well as a nonmagnetic layer formed between those first and second amorphous soft magnetic layers. The first and second amorphous soft magnetic layers are given uniaxial anisotropy in the radial direction of the substrate respectively and coupled with each other antiferromagnetically.

Perpendicular magnetic recording medium, manufacturing process of the same, and magnetic recording/reproducing apparatus using the same

Embodiments of the present invention help to provide an excellent perpendicular recording medium of high medium signal-to-noise (S/N) and with suppressed blurring in writing. According to one embodiment, a perpendicular recording layer is provided by way of a negative magnetic strain soft-magnetic underlayer above a substrate applied with texturing in the circumferential direction. The soft-magnetic underlayer has a first soft magnetic layer, a second soft magnetic layer and a nonmagnetic magnetic layer formed between the first soft magnetic layer and the second soft magnetic layer in which the first soft magnetic layer and the second soft magnetic layer are antiferromagnetically coupled to each other and the easy magnetization axis is directed in the radial direction.

Embodiments of the invention relate to easily achieving a perpendicular magnetic recording medium with high reliability and a magnetic recording apparatus with high recording density by improving the magnetic properties and surface smoothness of the soft magnetic underlayer and, moreover, enhancing adhesion with the substrate. In one embodiment, a perpendicular magnetic recording media composing a substrate, an adhesion layer formed on the substrate in which a second underlayer is laminated on a first underlayer, a soft magnetic underlayer formed on the second underlayer, an intermediate layer formed on the soft magnetic underlayer, a perpendicular recording layer formed on the intermediate layer, wherein the aforementioned first underlayer consists of an alloy composed of at least two elements selected from the group of Ni, Al, Ti, Ta, Cr, and Co, and the aforementioned second underlayer consists of Ta or a Ta-based amorphous structured alloy containing at least one element selected from the group of Ni, Al, Ti, Cr, and Zr.

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

Embodiments of the invention provide a medium which provides high media S/N and good corrosion resistance. According to one embodiment, in a perpendicular magnetic recording medium at least comprising a soft-magnetic underlayer, a seed layer, an intermediate layer, a magnetic recording layer and an overcoat layer which are stacked over a substrate in order, the magnetic recording layer has a granular structure which consists of many columnar grains of CoCrPt alloy and a grain boundary layer containing an oxide, the seed layer is made of TaNi alloy or TaTi alloy and the intermediate layer is made of Ru or Ru alloy which contains about 80 at. % Ru or more.

Perpendicular magnetic recording medium for high density recording and manufacturing of the same

Embodiments of the invention are directed to a medium which provides high media S/N and good corrosion resistance. According to one embodiment, in a perpendicular magnetic recording medium at least comprising a soft-magnetic underlayer, a seed layer, an intermediate layer, a magnetic recording layer and an overcoat layer which are stacked over a substrate in order, the magnetic recording layer has a granular structure which includes many columnar grains of CoCrPt alloy and a grain boundary layer containing an oxide, the seed layer is made of TaNi alloy or TaTi alloy and the intermediate layer is made of Ru or Ru alloy which contains 80 at. % Ru or more.

Perpendicular magnetic recording medium for high density magnetic recording and manufacturing of the same

Embodiments of the invention prevent demagnetization or degaussing of recorded magnetizations, even if a stray field is applied. In one embodiment, an output of a read head including a magneto-resistive effect element is inputted to a stray field detector through a DC amplifier and a DC filter. The stray field detector monitors dc components of the output from the read head, and escapes a head from above a magnetic recording medium.

Stray field detector, magnetic disk drive, and method of head escaping

A magnetic recording/reproducing apparatus is disclosed with high storage capability. The apparatus also prevents fluctuation of readback output and decay of magnetization or erasure of recorded magnetization in the recording layer. A soft magnetic underlayer and a perpendicular recording layer are formed in specific order on the substrate of a magnetic disk. The soft magnetic underlayer has a triple-layered structure in which a domain control layer, including an anti-ferromagnetic layer, is sandwiched between two first and second soft magnetic layers. The thickness of the first and second soft magnetic layers (d, d) is between 25 nm and 150 nm and a ratio of d/dis within a range of 0.3 to 1.5. Accordingly, magnetic domains in the soft magnetic underlayer of a perpendicular magnetic recording medium can be controlled and magnetic domain wall motion can be inhibited.

Perpendicular magnetic recording medium and magnetic recording/reproducing apparatus

A soft magnetic underlayer includes a first amorphous soft magnetic layer to which an exchange bias magnetic field is applied directly from an antiferromagnetic layer or via a ferromagnetic layer, and a second amorphous soft magnetic layer which is formed on the first amorphous soft magnetic layer via a non-magnetic layer. The first amorphous soft magnetic layer and the second amorphous soft magnetic layer are antiferromagnetically coupled.

Perpendicular magnetic recording medium, manufacturing process of the same, and magnetic storage apparatus using the same

A magnetoresistive sensor of the type of flowing a signal sensing current perpendicular to the plane, a magnetic head using the magnetoresistive sensor, and a magnetic disk apparatus, comprising a substrate, a pair of magnetic shield layers consisting of a lower magnetic shield layer and an upper magnetic shield layer, a magnetoresistive sensor layer, disposed between the pair of magnetic shield layers, an electrode terminal for flowing a signal current perpendicular to the plane of the magnetoresistive sensor layer, and magnetic domain control layers for controlling Barkhausen noise of the magnetoresistive sensor layer, the magnetic domain control layers being disposed in contact with opposite ends of the magnetoresistive sensor layer consist of a material having high electric resistivity and with a specific resistance not less than 10 m&#x3a9;cm.

Magnetoresistive sensor including magnetic domain control layers having high electric resistivity, magnetic head and magnetic disk apparatus

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Kanagawa, Japan

Reiko Arai