Patents Assigned to WD Media (Singapore) Pte. Ltd.
  • Patent number: 10083715
    Abstract: A method of manufacturing a perpendicular magnetic disk comprises forming, on a base, a film of a first ground layer made of Ru or a Ru alloy at a first pressure, forming, on the first ground layer, a film of a second ground layer made of Ru or a Ru alloy at a second pressure higher than a first pressure, forming, on the second ground layer, a film of a third ground layer having Ru or a Ru alloy as a main component and an oxide as an accessory component at a third pressure higher than the first pressure and lower than the second pressure, and forming, on a layer above the third ground layer, a film of a granular magnetic layer in which a non-magnetic substance having an oxide is segregated around magnetic particles having an CoCrPt alloy grown in a columnar shape to form a grain boundary.
    Type: Grant
    Filed: May 31, 2011
    Date of Patent: September 25, 2018
    Assignee: WD MEDIA (SINGAPORE) PTE.LTD.
    Inventors: Kazuaki Sakamoto, Takenori Kajiwara
  • Patent number: 9558778
    Abstract: A lubricant compound is contained in a lubrication layer of a magnetic disk in which at least a magnetic layer, a protective layer, and a lubrication layer are sequentially provided on a substrate, and the lubricant compound contains a component A represented by Chemical formula 1 and a component B represented by Chemical formula 2: wherein X in Chemical formula 1 represents OH wherein X in Chemical formula 2 represents OCH2CH(OH)CH2OH, and the lubricant compound further contains a component C made of a specific compound having a phosphezene ring in the structure thereof.
    Type: Grant
    Filed: March 27, 2010
    Date of Patent: January 31, 2017
    Assignee: WD Media (Singapore) Pte. Ltd.
    Inventors: Kota Suzuki, Koichi Shimokawa, Katsushi Hamakubo, Kae Itoh
  • Patent number: 9472227
    Abstract: [Problem] An object is to provide a perpendicular magnetic recording medium that can realize both improvement in crystal orientation and refinement of crystal grain size and can achieve a higher recording density and a higher SN ratio, and a method of manufacturing the same. [Solution] A perpendicular magnetic recording medium 100 of the present invention is a perpendicular magnetic recording medium 100 having a base plate 100, and a laminate film including a first ground layer 150a provided on the base plate 100, a second ground layer 150b provided on the first ground layer 150a, and a main recording layer 160 provided on the second ground layer 150b and containing a magnetic material having a granular structure, wherein the magnetic material which constitutes the main recording layer 160 contains a CoCrPt alloy, and a material which constitutes the second ground layer 150b contains an Ru—Co oxide alloy.
    Type: Grant
    Filed: June 22, 2011
    Date of Patent: October 18, 2016
    Assignee: WD Media (Singapore) Pte. Ltd.
    Inventors: Hi Shin, Iwao Okamoto
  • Patent number: 9424873
    Abstract: A method of manufacturing a perpendicular magnetic recording medium 100 that includes forming a magnetic recording layer 122 on a disk base 110, then forming a resist layer 130 on the magnetic recording layer, and a patterning step of processing the resist layer so as to vary the thickness of the resist layer partially, thereby forming a predetermined pattern having a recessed part and a projected part. Finally, the method includes implanting ions into a plurality of layers including the magnetic recording layer with the resist layer interposed. At the ion implanting step, (1) one or more of said plurality of layers to be implanted with ions is determined by selectively applying an energy amount to implant ions, and (2) a total amount of ions to be implanted into each of said one or more of said plurality of layers is determined by selectively applying said energy amount for a respective time period for said one or more of said plurality of layers.
    Type: Grant
    Filed: February 19, 2010
    Date of Patent: August 23, 2016
    Assignee: WD Media (Singapore) Pte. Ltd
    Inventors: Masanori Aniya, Yoshiaki Sonobe
  • Patent number: 9349404
    Abstract: [Problem] A perpendicular magnetic disk with an improved SNR and an increased recording density by further improving crystal orientation of a preliminary ground layer formed of an Ni-base alloy is provided. [Solution] A typical structure of the perpendicular magnetic disk according to the present invention includes, on a base 110, a soft magnetic layer 130, a Ta alloy layer 140 provided on the soft magnetic layer 130, an Ni alloy layer 142 provided on the Ta alloy layer 140, a ground layer 150 provided on the Ni alloy layer 142 and having Ru as a main component, and a granular magnetic layer 160 provided on the ground layer 150. The Ta alloy layer 140 is a layer containing 10 atomic percent or more and 45 atomic percent or less Ta and having amorphous and soft magnetic properties.
    Type: Grant
    Filed: May 31, 2011
    Date of Patent: May 24, 2016
    Assignee: WD Media (Singapore) PTE. LTD
    Inventors: Teiichiro Umezawa, Kazuaki Sakamoto
  • Patent number: 9245568
    Abstract: Disclosed is a magnetic disk that has excellent durability, particularly excellent LUL durability, and excellent alumina resistance and has a high level of reliability under a low flying height of a magnetic head involved in a recent tendency toward a rapid increase in recording density and a very severe environment resistance requirement due to diversified applications. A magnetic disk (10) comprises a substrate (1) and at least a magnetic layer (6), a carbon-based protective layer (7), and a lubricating layer (8) provided in that order over the substrate (1). The lubricating layer (8) contains a compound that has a perfluoropolyether main chain in the structure thereof and has an aromatic group and a polar group at the end of the molecule.
    Type: Grant
    Filed: March 27, 2009
    Date of Patent: January 26, 2016
    Assignee: WD Media (Singapore) Pte. Ltd.
    Inventors: Kae Itoh, Katsushi Hamakubo
  • Patent number: 9240204
    Abstract: A perpendicular magnetic disk is provided. The disk includes, on a base and in the order from bottom, a first granular magnetic layer group including a plurality of magnetic layers each having a granular structure, a non-magnetic layer having Ru or a Ru alloy as a main component, a second granular magnetic layer group including a plurality of magnetic layers each having the granular structure, and an auxiliary recording layer having a CoCrPtRu alloy as a main component. Layers closer to a front surface among the plurality of magnetic layers included in the first granular magnetic layer group having an equal or smaller content of Pt. Layers closer to the front surface among the plurality of magnetic layers included in the second granular magnetic layer group having an equal or smaller content of Pt and having an equal or larger content of an oxide.
    Type: Grant
    Filed: May 20, 2011
    Date of Patent: January 19, 2016
    Assignee: WD Media (Singapore) Pte. Ltd.
    Inventors: Teiichiro Umezawa, Takenori Kajiwara, Tokichiro Sato
  • Patent number: 9183869
    Abstract: A perpendicular magnetic recording medium 100 having a magnetic recording layer 122, wherein a particle diameter of crystal grains in layer 122 improves a SNR while a high coercive force is maintained. There also is at least a ground layer 118, a first magnetic recording layer 122a, and a second magnetic recording layer 122b in this order on a disk base 110. The first layer 122a and the second layer 122b are ferromagnetic layers, each having a granular structure in which a grain boundary part made of a non-magnetic substance is formed between crystal grains each grown in a columnar shape, and A<B when an average particle diameter of the crystal grains in the first magnetic recording layer 122a is taken as A nm and an average particle diameter of the crystal grains in the second magnetic recording layer 122b is taken as B nm.
    Type: Grant
    Filed: October 10, 2013
    Date of Patent: November 10, 2015
    Assignee: WD Media (Singapore) Pte. Ltd.
    Inventor: Takahiro Onoue
  • Patent number: 9159351
    Abstract: 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.
    Type: Grant
    Filed: October 14, 2008
    Date of Patent: October 13, 2015
    Assignee: WD Media (Singapore) PTE. LTD
    Inventors: Kazuaki Sakamoto, Kong Kim, Takahiro Onoue, Masafumi Ishiyama, Teiichiro Umezawa, Kenji Ayama
  • Patent number: 9142241
    Abstract: A perpendicular magnetic recording medium comprises a magnetic recording layer that records a signal, an underlayer formed of Ru or Ru compound below the magnetic recording layer, a non-magnetic layer formed of a non-magnetic material below the underlayer to control crystal orientation of the underlayer, a soft magnetic layer provided below the non-magnetic layer, and a substrate on which the magnetic recording layer, the underlayer, the non-magnetic layer, and the soft magnetic layer are formed. The non-magnetic layer comprises a first non-magnetic layer formed above the soft magnetic layer and a second non-magnetic layer formed above the first non-magnetic layer. The first non-magnetic layer is formed of amorphous Ni compound while the second non-magnetic layer is formed of crystalline Ni or crystalline Ni compound.
    Type: Grant
    Filed: April 23, 2013
    Date of Patent: September 22, 2015
    Assignee: WD Media (Singapore) Pte. Ltd.
    Inventors: Takahiro Onoue, Tokichiro Sato, Takenori Kajiwara
  • Patent number: 9142238
    Abstract: In a method of manufacturing a magnetic disk including at least a magnetic recording layer on a substrate 1 and used for vertical magnetic recording, in a step of forming, on the substrate 1, the magnetic recording layer composed of a ferromagnetic layer 5 having a granular structure and an exchange energy control layer 7 constituted by a laminated layer formed on the ferromagnetic layer 5, at least the exchange energy control layer 7 is formed through sputtering in an atmosphere of a rare gas having a greater mass than an argon gas. The rare gas having a greater mass than the argon gas is a krypton (Kr) gas, for example. The exchange energy control layer 7 is a laminated layer composed of a first layer containing Co or a Co-alloy and a second layer containing palladium (Pd) or platinum (Pt), for example.
    Type: Grant
    Filed: March 29, 2007
    Date of Patent: September 22, 2015
    Assignee: WD Media (Singapore) Pte. Ltd.
    Inventors: Kim Kong, Jo Alvin Dumaya
  • Patent number: 9093100
    Abstract: A magnetic recording medium enabling excellent magnetic recording reproduction characteristics to be exhibited with the spacing loss reduced. The magnetic recording medium has a magnetic recording layer of a granular structure having nonmagnetic boundary portions between pillar-shaped magnetic particles on a nonmagnetic substrate, and an exchange coupling layer provided on the magnetic recording layer to add an action of exchange coupling the magnetic particles. Ion irradiation on the entire surface of the exchange coupling layer after layering the exchange coupling layer on the magnetic recording layer is performed.
    Type: Grant
    Filed: March 22, 2013
    Date of Patent: July 28, 2015
    Assignee: WD Media (Singapore) Pte. Ltd.
    Inventors: Junichi Yasumori, Yoshiaki Sonobe
  • Patent number: 9082444
    Abstract: [PROBLEMS] To appropriately form a DTR medium, a patterned medium, or the like in a manner less likely to cause the problems of prolonged process time and increased cost. [MEANS FOR SOLVING PROBLEMS] A perpendicular magnetic recording layer 22 has a plurality of tracks 102 which define recording regions extending in a scanning direction of a magnetic head and which are arranged in parallel in a direction intersecting with the scanning direction. The perpendicular magnetic recording layer 22 has a guard band region 104 formed on its surface and provided with a groove portion 202 which extends along the tracks 102. In a cross-section of the perpendicular magnetic recording layer 22 taken along a plane perpendicular to the scanning direction, the maximum depth D of the groove portion 202 is in the range of 0.5 to 10 nm with reference to an average height (broken line 302) of the tracks 102 between which the groove portion 202 is interposed.
    Type: Grant
    Filed: March 28, 2008
    Date of Patent: July 14, 2015
    Assignee: WD Media (Singapore) Pte. Ltd.
    Inventors: Shinichi Ishibashi, Akira Shimada
  • Patent number: 9064518
    Abstract: An object of the present invention is to provide a perpendicular magnetic recording medium the SNR of which is further improved while a high coercive force Hc is secured so that a higher recoding density can be achieved.
    Type: Grant
    Filed: September 16, 2009
    Date of Patent: June 23, 2015
    Assignee: WD Media (Singapore) Pte. Ltd.
    Inventors: Takahiro Onoue, Teiichiro Umezawa
  • Patent number: 9047903
    Abstract: An object of the present invention is to provide a perpendicular magnetic recording medium in which each space between crystal grains of a first magnetic recording layer is so designed as to allow the layer to also have a function as a continuous layer, and a method of manufacturing a perpendicular magnetic recording medium. In a perpendicular magnetic recording medium 100 according to the present invention, a first magnetic recording layer 122a and a second magnetic recording layer 122b are ferromagnetic layers each having a granular structure in which a grain boundary part made of a non-magnetic substance is formed between crystal grains each grown in a column shape and, in the first magnetic recording layer 122a, an intergranular distance defined by an average of shortest distances between grain boundary parts each between a crystal grain and its adjacent crystal grain is equal to or shorter than 1 nm.
    Type: Grant
    Filed: March 26, 2009
    Date of Patent: June 2, 2015
    Assignee: WD Media (Singapore) Pte. Ltd.
    Inventor: Takahiro Onoue
  • Patent number: 8999534
    Abstract: A lubricant for a magnetic disk that is excellent in heat resistance and is suitably used in a magnetic disk to be mounted on a magnetic recording device of a thermally assisted magnetic recording system and a magnetic disk provided with a lubricant layer containing this lubricant. The lubricant for a magnetic disk contains a compound where perfluoropolyether groups each having a perfluoropolyether main chain in its structure and a phosphazene ring at an end are linked to each other through a linking group. The linking group is an aliphatic group or a phosphazene ring. In a magnetic disk having at least a magnetic recording layer, a protective layer, and a lubricant layer on a substrate, the lubricant layer contains the lubricant for a magnetic disk.
    Type: Grant
    Filed: June 22, 2010
    Date of Patent: April 7, 2015
    Assignee: WD Media (Singapore) Pte. Ltd.
    Inventors: Koichi Shimokawa, Katsushi Hamakubo
  • Patent number: 8999533
    Abstract: Provided is a magnetic disk comprising a lubricating layer formed of a lubricant. The lubricant constituting the lubricating layer has excellent properties, for example, excellent fluidity, surface energy, and CFT properties. By virtue of the excellent properties, the magnetic disk has a high level of reliability despite a low flying height of a magnetic head due to a recent rapid increase in recording density and a very severe environment resistance requirement due to diversification of applications. The magnetic disk comprises a substrate and at least a magnetic layer, a protective layer, and a lubricating layer provided in that order over the substrate.
    Type: Grant
    Filed: March 27, 2009
    Date of Patent: April 7, 2015
    Assignee: WD Media (Singapore) Pte. Ltd.
    Inventor: Koichi Shimokawa
  • Patent number: 8999535
    Abstract: [Problem] An object is to provide a perpendicular magnetic recording medium in which a narrower track width is achieved by enhancing an exchange coupling magnetic field Hex of a soft magnetic layer so that a higher recording density can be achieved. [Solution] A perpendicular magnetic recording medium according to the present invention is configured to include a magnetic recording layer 122 that records a signal, and a soft magnetic layer 114 provided below the magnetic recording layer, on a base 110 on a main surface of which textures are formed, wherein the textures includes first textures 110a that is linear rails in a certain direction, and second textures 110b that are trails intersecting at a predetermined angle with the first textures; and the angle of intersection between the first textures and the second textures is 10° or less.
    Type: Grant
    Filed: May 31, 2011
    Date of Patent: April 7, 2015
    Assignee: WD Media (Singapore) PTE, Ltd
    Inventor: Toshiaki Tachibana
  • Patent number: 8951651
    Abstract: [Problem] A perpendicular magnetic disk with an improved SNR and increased recording density by further advancing microfabrication and uniformalization of particle diameters and improving crystal orientation regarding a preliminary ground layer made of a Ni-base alloy is provided. [Solution] The perpendicular magnetic disk includes: on a base 110, a first Ni alloy layer 142 and a second Ni alloy layer 144; a ground layer 150 having Ru as a main component; and a perpendicular magnetic recording layer 160 containing a CoPt-base alloy and an oxide in this order, the first Ni alloy layer 142 and the second Ni alloy layer 144 including at least one element that takes a bcc crystal structure as a simple substance, and the second Ni alloy layer 144 further including an oxide.
    Type: Grant
    Filed: May 31, 2011
    Date of Patent: February 10, 2015
    Assignee: WD Media (Singapore) Pte. Ltd.
    Inventor: Kazuaki Sakamoto
  • Patent number: 8922936
    Abstract: An object of the present invention is to further improve a recording density in a magnetic disk apparatus using a shingle write system. In a magnetic disk apparatus including a magnetic disk, a recording head that writes information on the magnetic disk, and a controller that controls a writing operation of the recording head to the magnetic disk, the controller controls the writing operation such that the recording head writes information on a region including a target track and a portion of track adjacent thereto in an overlapping manner while position-shifting in a radial direction of the magnetic disk and a first writing frequency to a track on which information is last written is higher than a second writing frequency to another track.
    Type: Grant
    Filed: March 24, 2011
    Date of Patent: December 30, 2014
    Assignee: WD Media (Singapore) Pte. Ltd.
    Inventors: Iwao Okamoto, Chiyo Saito, Daisuke Masuda