Magnetic Layers Separated By Nonmagnetic (antiferromagnetic, Cu, Dielectric, Etc.) Layer(s) Patents (Class 428/828)
  • Publication number: 20080124581
    Abstract: A TMR element includes a lower magnetic layer, an upper magnetic layer, and a tunnel barrier layer of crystalline insulation material sandwiched between the lower magnetic layer and the upper magnetic layer. The lower magnetic layer includes a first magnetic layer and a second magnetic layer sandwiched between the first magnetic layer and the tunnel barrier layer. The second magnetic layer is formed from a magnetic material containing at least one of Fe, Co and Ni.
    Type: Application
    Filed: November 26, 2007
    Publication date: May 29, 2008
    Applicant: TDK CORPORATION
    Inventors: Satoshi MIURA, Takumi YANAGISAWA
  • Publication number: 20080124583
    Abstract: 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.
    Type: Application
    Filed: November 9, 2007
    Publication date: May 29, 2008
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Reiko Arai, Hiroyuki Suzuki, Masayoshi Shimizu
  • Publication number: 20080118780
    Abstract: A discrete track type perpendicular magnetic recording medium having good crystal orientation and perpendicular magnetic anisotropy of a magnetic recording layer is disclosed. The medium is produced by a simple, inexpensive method. A soft magnetic backing layer, a base layer for crystal orientation, and a perpendicular magnetic recording layer are formed in this order on a nonmagnetic substrate, and a processing layer having a concavo-convex pattern comprising convex parts at a low density and concave parts at a higher density is provided between the nonmagnetic substrate and the perpendicular magnetic recording layer, the concavo-convex pattern shape of the processing layer being reflected on the perpendicular magnetic recording layer.
    Type: Application
    Filed: November 20, 2007
    Publication date: May 22, 2008
    Applicant: FUJI ELECTRIC DEVICE TECHNOLOGY CO., LTD.
    Inventor: Hisato KATO
  • Patent number: 7368184
    Abstract: A magnetic recording medium which has a high areal density and reduced power consumption for recording operations, and a magnetic recording device incorporating the magnetic recording medium. The magnetic recording medium has an upper soft magnetic layer formed uniformly along a plane including the upper surface of a recording layer over the convex and concave portions of a concavo-convex pattern in the recording layer.
    Type: Grant
    Filed: September 24, 2004
    Date of Patent: May 6, 2008
    Assignee: TDK Corporation
    Inventors: Akimasa Kaizu, Yoshikazu Soeno
  • Patent number: 7357998
    Abstract: 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.
    Type: Grant
    Filed: January 16, 2004
    Date of Patent: April 15, 2008
    Assignee: Hoya Corporation
    Inventors: Kong Kim, Junichi Horikawa
  • Patent number: 7327528
    Abstract: A magnetic recording method for recording information on a medium with a first magnetic layer, a second magnetic layer, and a non-magnetic coupling layer provided between the first and second magnetic layers so that these two layers are exchange-coupled and the first magnetic layer has an exchange coupling field Hex1 larger than both a coercivity Hc1 of the first magnetic layer and a coercivity Hc2 of the second magnetic layer. The method includes limiting a magnetic field applied to the magnetic recording medium during recording to a range so that magnetizations of the first and second magnetic layers are maintained in either a first antiparallel state or a second antiparallel state, without entering into a parallel state, whereby in the second antiparallel state the magnetizations of the first magnetic layer and the second magnetic layer are reversed, but still antiparallel, relative to the magnetization in the first antiparallel state.
    Type: Grant
    Filed: April 17, 2006
    Date of Patent: February 5, 2008
    Assignee: Fujitsu Limited
    Inventor: Akihiro Inomata
  • Publication number: 20070287031
    Abstract: A perpendicular magnetic recording system, comprises: a perpendicular magnetic recording medium including a non-magnetic substrate having a surface and a stacked plurality of thin film layers forming a layer stack overlying the substrate surface and including a magnetically soft underlayer (SUL) beneath at least one perpendicular magnetic recording layer, wherein the SUL has a saturation magnetization (Ms)—thickness (t) product (Mst) less than about 4 memu/cm2, and a ring-type magnetic transducer head is positioned in spaced adjacency to an upper surface of the layer stack.
    Type: Application
    Filed: June 8, 2006
    Publication date: December 13, 2007
    Inventors: Thomas P. Nolan, Li Tang, Yong-Chang Feng, Zhong (Stella) Wu, Samuel D. Harkness, Hans J. Richter, Youfeng Zheng
  • Patent number: 7279240
    Abstract: A laminated perpendicular magnetic recording medium comprises a non-magnetic substrate and at least a pair of polycrystalline, vertically stacked, spaced-apart perpendicular magnetic layers supported thereon, wherein each of the magnetic layers has substantially the same preferred out-of-plane crystal growth orientation and the grains of at least two of the magnetic layers are vertically uncorrelated with each other.
    Type: Grant
    Filed: January 27, 2004
    Date of Patent: October 9, 2007
    Assignee: Seagate Technology LLC
    Inventor: Thomas Patrick Nolan
  • Publication number: 20070218316
    Abstract: A magnetic recording medium according to one aspect of the present invention includes a substrate; an underlayer positioned on the substrate and made of a material having a body-centered-cubic crystalline structure or a B2 crystalline structure; a first intermediate layer positioned on the underlayer and having a hexagonal closest packing crystalline structure, and being made of Co or a Co alloy; a second intermediate layer positioned on the first intermediate layer and having a hexagonal closest packing crystalline structure, and being made of a material selected from the group consisting of Ru, Ti, Re, Zr, Hf, and a Ru alloy; and a magnetic layer positioned on the second intermediate layer and including multiple magnetic grains each having a hexagonal closest packing crystalline structure and an axis of easy magnetization oriented in a direction substantially parallel to a surface of the substrate, wherein the magnetic grains are isolated from each other.
    Type: Application
    Filed: June 26, 2006
    Publication date: September 20, 2007
    Applicant: FUJITSU LIMITED
    Inventor: Akihiro Inomata
  • Patent number: 7271984
    Abstract: A magnetic recording medium is provided with a first magnetic layer, a nonmagnetic coupling layer provided on the first magnetic layer, and a second magnetic layer provided on the nonmagnetic coupling layer. The first and second magnetic layers are exchange-coupled, and have magnetization directions which are mutually parallel in a state where no external magnetic field is applied thereto, and the first magnetic layer switches the magnetization direction thereof before the second magnetic layer in response to a recording magnetic field which switches the magnetization directions of the first and second magnetic layers.
    Type: Grant
    Filed: May 21, 2004
    Date of Patent: September 18, 2007
    Assignee: Fujitsu Limited
    Inventors: Hisashi Umeda, Iwao Okamoto
  • Patent number: 7238385
    Abstract: A disk for a hard disk drive. The disk includes a S1 layer of magnetic material located over a substrate, and a layer of ruthenium located over the S1 layer. The disk further includes a top layer of magnetic material and a layer of chromium located adjacent to the top magnetic layer. The chromium diffuses into the top layer of magnetic material to magnetically decouple the grains of the magnetic material. Decoupling the grains of the magnetic material reduces the magnetic noise of the disk and improves the signal to noise ratio of the hard disk drive.
    Type: Grant
    Filed: November 23, 2004
    Date of Patent: July 3, 2007
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Sooyoul Hong, Hyung Lee
  • Patent number: 7232620
    Abstract: A magnetic recording medium includes a first magnetic layer, a second magnetic layer, and a non-magnetic coupling layer provided between the first and second magnetic layers so that the first and second magnetic layers are exchange-coupled and the magnetizations of the first and second magnetic layers are antiparallel. The first magnetic layer has an exchange coupling field Hex1 which is larger than the respective coercivities Hc1 and Hc2 of the first and second magnetic layers.
    Type: Grant
    Filed: October 23, 2003
    Date of Patent: June 19, 2007
    Assignee: Fujitsu Limited
    Inventor: Akihiro Inomata
  • Patent number: 7179548
    Abstract: First magnetic crystalline grains are located at spaced positions on the surface of a base layer in a polycrystalline structure film. Magnetic interaction can reliably be prevented between the adjacent first magnetic crystalline grains. An amorphous material or a non-magnetic material covers over the first magnetic crystalline grains. An orientation controlling layer covering over the first magnetic crystalline grains and the amorphous or non-magnetic material on the base layer. Second magnetic crystalline grains are located at spaced locations on the surface of the orientation controlling layer. The orientation controlling layer serves to set the orientation in a predetermined direction in the second magnetic crystalline grains. Since the orientation of the magnetic crystalline grains can be aligned in a predetermined direction, the magnetic field of a sufficient intensity can be leaked out of the polycrystalline structure film.
    Type: Grant
    Filed: December 8, 2004
    Date of Patent: February 20, 2007
    Assignee: Fujitsu Limited
    Inventor: Ryoichi Mukai
  • Patent number: 7174622
    Abstract: A method of fabrication of a slider includes forming a first ferromagnetic layer, a second ferromagnetic layer, and an antiferromagnetic layer and applying a layer of protective material to proximal ends of those layers that are proximal to the disk surface. The method further includes recessing a proximal end of a non-magnetic metal layer formed on the first ferromagnetic layer from the disk surface to form at least one recessed area. The method also includes filling the recessed area with protective material to a depth such that when the layer of protective material is worn from the ends of the first ferromagnetic layer, the second ferromagnetic layer, and the antiferromagnetic layer by burnishing of the ends by the disk surface, protective material still remains in the recessed area of the non-magnetic metal layer.
    Type: Grant
    Filed: February 20, 2004
    Date of Patent: February 13, 2007
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Dallas W. Meyer, Tien-Chih Lin, Michael A. Stacy
  • Patent number: 7172824
    Abstract: A laminated perpendicular magnetic recording medium comprises a non-magnetic substrate and at least a pair of polycrystalline, vertically stacked, spaced-apart perpendicular magnetic layers supported thereon, wherein each of the magnetic layers has substantially the same preferred out-of-plane crystal growth orientation and the grains of at least two of the magnetic layers are vertically uncorrelated with each other.
    Type: Grant
    Filed: January 27, 2004
    Date of Patent: February 6, 2007
    Assignee: Seagate Technology LLC
    Inventor: Thomas Patrick Nolan
  • Patent number: 7166374
    Abstract: A magnetic recording medium comprising a non-ferromagnetic substrate and a magnetic recording film formed on the substrate with an underlayer interposed therebetween, wherein the magnetic recording film comprises a plurality of magnetic layers and an interlayer made of a material having a B2 crystal structure or an interlayer made of Ru, disposed between the adjacent magnetic layers.
    Type: Grant
    Filed: March 23, 2004
    Date of Patent: January 23, 2007
    Assignee: Komag, Inc.
    Inventors: Michinobu Suekane, Makoto Imakawa, Takehiko Hiruma
  • Patent number: 7149045
    Abstract: A magnetic recording device including a longitudinal magnetic recording medium. The longitudinal magnetic recording medium includes a magnetically soft underlayer disposed under a longitudinal recording layer. A perpendicular write head is utilized to write data to the longitudinal magnetic recording medium wherein the longitudinal recording layer is disposed within an effective write gap formed by the perpendicular write head and the underlayer. The longitudinal component of the perpendicular write head is sufficient to switch the magnetic grains in the recording layer in the presence of the perpendicular field. The magnetic recording medium can have a high areal density and improved magnetic properties.
    Type: Grant
    Filed: October 30, 2003
    Date of Patent: December 12, 2006
    Assignee: Maxtor Corporation
    Inventors: Michael L. Mallary, Steven Marshall, Mourad Benakli, Adam F. Torabi
  • Patent number: 7144641
    Abstract: This invention relates to a magnetic backlayer, and provides a magnetic backlayer giving a small spike noise spk and a small media noise Nm and exhibiting a large saturation magnetization Ms to have a good soft magnetic property. The magnetic backlayer is formed on a substrate; has a structure in that soft magnetic layers comprising iron and carbon as main components and nonmagnetic layers are alternately laminated; and has easy axes of magnetization in the in-plane direction of the film and the radius direction of the substrate.
    Type: Grant
    Filed: December 30, 2004
    Date of Patent: December 5, 2006
    Assignee: Fujitsu Limited
    Inventors: Hiroyasu Kawano, Takeshi Morikawa, Koji Matsumoto, Satomi Kubo
  • Patent number: 7144640
    Abstract: A digital storage medium for use in data storage devices has two magnetic layers where the respective easy axes of the magnetic moments in the two layers are perpendicular to each other. Exchange coupling of the magnetic moments in the magnetic layers produces a resultant magnetic moment that is tilted out of the plane of the digital storage medium. The resultant magnetic moment of the medium allows the use of either a ring head, a single pole head, or a head that generates a field tilted at an angle for write operations.
    Type: Grant
    Filed: August 1, 2003
    Date of Patent: December 5, 2006
    Assignee: Agency for Science, Technology and Research
    Inventors: Ching Hian Hee, Jian Ping Wang, Haibao Zhao
  • Patent number: 7141315
    Abstract: 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.
    Type: Grant
    Filed: July 31, 2003
    Date of Patent: November 28, 2006
    Assignees: Showa Denko K.K., Kabushiki Kaisha Toshiba
    Inventors: Kenji Shimizu, Akira Sakawaki, Hiroshi Sakai, Takashi Hikosaka, Futoshi Nakamura
  • Patent number: 7141316
    Abstract: 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?density recording by further decreasing the grain size of the perpendicular magnetic recording layer.
    Type: Grant
    Filed: March 17, 2004
    Date of Patent: November 28, 2006
    Assignees: Kabushiki Kaisha Toshiba, Showa Denko K. K.
    Inventors: Takeshi Iwasaki, Takashi Hikosaka, Soichi Oikawa, Futoshi Nakamura, Tomoyuki Maeda, Hiroshi Sakai, Kenji Shimizu, Akira Sakawaki
  • Patent number: 7138195
    Abstract: A double layer perpendicular magnetic recording medium having a high medium S/N ratio at a recording density of 50 Gb/in2 or higher and a magnetic storage apparatus with a lower error rate and excellent reliability are provided. In a perpendicular magnetic recording medium in which a soft magnetic underlayer 12, an intermediate layer 13, and a perpendicular magnetic recording layer 14 are sequentially formed on a substrate 11, the intermediate layer 13 is made to be a non-magnetic amorphous alloy, in which Ni is a main component and Zr is contained, and the soft magnetic underlayer 12 is constituted of ferromagnetic nan-crystals precipitated by annealing.
    Type: Grant
    Filed: April 28, 2004
    Date of Patent: November 21, 2006
    Assignee: Hitachi, Ltd.
    Inventors: Kiwamu Tanahashi, Atsushi Kikugawa, Yukio Honda, Masaaki Futamoto, Akira Ishikawa
  • Patent number: 7138194
    Abstract: The magnetic recording medium comprises a soft magnetic undercoat film, an orientation control film that controls the orientation of a film provided directly above, a perpendicular magnetic film of which axis of easy magnetization is generally oriented perpendicular to a non-magnetic substrate, and a protective film, that are provided on the non-magnetic substrate, wherein the orientation control film is made of a Co alloy which contains one or more elements selected from Ti, V, Sr, Y, Nb, Mo, Hf, Ta, Ni and W.
    Type: Grant
    Filed: July 31, 2003
    Date of Patent: November 21, 2006
    Assignees: Showa Denko K.K., Kabushiki Kaisha Toshiba
    Inventors: Kenji Shimizu, Akira Sakawaki, Hiroshi Sakai, Takashi Hikosaka, Soichi Oikawa
  • Patent number: 7128987
    Abstract: Multilayer magnetic structures comprising composite layers and spacer layers are disclosed. The composite layers include a discontinuous magnetic phase such as Co, Ni or Fe platelets, and a continuous nonmagnetic phase such as C, AlOx, SiOx, ZrOx, Cu, Ag and Au. The spacer layers may comprise Pt, Pd, Au or the like. The composite layers and spacer layers may be made by sputtering. The multilayer structures are useful as magnetic recording layers of magnetic recording media. In one embodiment, the recording media comprises a perpendicular magnetic recording medium including a substrate, a soft magnetic underlayer, a seed layer and the multilayer structure.
    Type: Grant
    Filed: January 6, 2003
    Date of Patent: October 31, 2006
    Assignee: Seagate Technology LLC
    Inventors: Rene Johannes Marinus van de Veerdonk, Duane Clifford Karns, Dieter Klaus Weller, Yukiko Kubota
  • Patent number: 7125615
    Abstract: The magnetic recording medium includes a seed layer and a magnetic recording layer formed on the seed layer. The magnetic recording layer is provided with a plurality of laminated layers and a noble metal layer. The laminated layer includes a transition metal element layer and a platinum group element layer. The noble metal layer is interposed between the laminated layers. The magnetic recording medium satisfies the relational expression 0<Y/X?1.0, where X is the thickness of the seed layer, and Y is the sum total of the thickness of the noble metal layer in the magnetic recording layer.
    Type: Grant
    Filed: November 26, 2003
    Date of Patent: October 24, 2006
    Assignee: TDK Corporation
    Inventors: Shuichi Okawa, Takahiro Suwa
  • Patent number: 7087325
    Abstract: The present invention relates to a magnetic recording medium, which has excellent magnetic characteristics. The present invention also relates to a method for producing a magnetic recording medium where a plurality of targets are repeatedly sputtered several times in sequential order to form non-magnetic and magnetic films on a substrate.
    Type: Grant
    Filed: February 11, 2003
    Date of Patent: August 8, 2006
    Assignee: Showa Denko Kabushiki Kaisha
    Inventors: Hiroshi Kanazawa, Hiroshi Sakai, Hiroshi Ohsawa, Kazunori Ohnami
  • Patent number: 7083870
    Abstract: 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 has a material composition forming a C11b structure. 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.
    Type: Grant
    Filed: July 14, 2003
    Date of Patent: August 1, 2006
    Assignees: Showa Denko K. K., Kabushiki Kaisha Toshiba
    Inventors: Kenji Shimizu, Akira Sakawaki, Hiroshi Sakai, Takashi Hikosaka, Takeshi Iwasaki
  • Patent number: 7081308
    Abstract: In a magnetic recording medium including a substrate (1) having a principal surface on which first and second magnetic layers (5 and 7) and a spacer layer (6) are at least formed, each of the first and the second magnetic layers being of a ferromagnetic material, the spacer layer being formed between the first and the second magnetic layers for inducing antiferromagnetic exchange interaction between the first and the second magnetic layers, the principal surface of the substrate is provided with concentric textures to have a predetermined surface roughness so that the spacer layer has a uniform thickness. The first magnetic layer is for controlling the antiferromagnetic exchange interaction.
    Type: Grant
    Filed: June 2, 2004
    Date of Patent: July 25, 2006
    Assignees: Hoya Corporation, Hoya Magnetics Singapore Pte. Ltd.
    Inventors: Hisao Kawai, Teiichiro Umezawa, Hirotaka Tanaka, Masaki Uemura
  • Patent number: 7070870
    Abstract: A magnetic recording medium includes a substrate, an underlayer, a lower magnetic layer formed on the underlayer, an intermediate layer, and an upper magnetic layer formed on the intermediate layer. The intermediate layer is typically Ru, and promotes anti ferromagnetic coupling between the upper and lower magnetic layers. The upper and lower magnetic layers are typically Co alloys. The lower magnetic layer has a high saturation magnetization Ms to promote high exchange coupling between the upper and lower magnetic layers. The dynamic coercivity of the lower magnetic layer is lower than the exchange field to ensure rapid switching of the lower magnetic layer.
    Type: Grant
    Filed: February 1, 2005
    Date of Patent: July 4, 2006
    Assignee: Komag, Inc.
    Inventors: Gerardo Bertero, Sudhir Malhotra, David Wachenschwanz, Zhengsheng Shan, Donald Stafford
  • Patent number: 7060374
    Abstract: There are provided a magnetic thin film utilizing a granular film and having excellent high frequency characteristics and a method of manufacturing the same, and a multilayered magnetic film and magnetic components and electronic equipment utilizing the same. A nonreactive sputtering is performed so that there is no oxidation of a magnetic metal, and a saturation magnetization is increased to increase a resonant frequency of permeability. Also, a multi-target simultaneous sputtering is combined with the nonreactive sputtering so that in a granular structure including magnetic grains and an insulating layer a size of the magnetic grains and a thickness of the insulating layer are optimized thereby ensuring a proper magnitude for a crystalline magnetic anisotropy within the grains and excellent soft magnetic properties.
    Type: Grant
    Filed: May 11, 2004
    Date of Patent: June 13, 2006
    Assignee: Taiyo Yuden Co., Ltd.
    Inventors: Kazuyoshi Kobayashi, Kenji Ikeda, Masayuki Fujimoto
  • Patent number: 7045225
    Abstract: A perpendicular magnetic recording suitable for mass production and having suppressed spike noise has at least a seed layer, an orientation controlling layer, an antiferromagnetic layer, a soft magnetic layer, a magnetic recording layer, a protective layer, and a liquid lubricant layer formed on a nonmagnetic substrate. The orientation controlling layer is composed of a material comprising at least Ni and Fe, and having at least one element selected from the group consisting of B, Nb, and Si. The seed layer is composed of Ta. Further, after depositing the antiferromagnetic layer and the soft magnetic layer, but before depositing the magnetic recording layer, the substrate is heated to a blocking temperature or higher, and thereafter cooled to the blocking temperature or below while applying a static magnetic field in a radial direction of the substrate.
    Type: Grant
    Filed: November 26, 2003
    Date of Patent: May 16, 2006
    Assignee: Fuji Electric Device Technology Co., Ltd.
    Inventors: Sadayuki Watanabe, Yasushi Sakai
  • Patent number: 7033684
    Abstract: A magnetic recording medium comprising at least a soft magnetic layer, an orientation control film that controls the orientation of a film provided directly thereabove, an intermediate film, a perpendicular magnetic recording film of which the axis of easy magnetization is generally oriented perpendicular to a non-magnetic substrate, and a protective film, that are provided on said substrate, wherein the intermediate film has saturation magnetization Ms of at least 20 (emu/cc) and equal to or less than 200 (emu/cc), a method of manufacture thereof, and a magnetic read/write apparatus.
    Type: Grant
    Filed: July 14, 2003
    Date of Patent: April 25, 2006
    Assignees: Showa Denko K.K., Kabushiki Kaisha Toshiba
    Inventors: Kenji Shimizu, Akira Sakawaki, Hiroshi Sakai, Takashi Hikosaka, Soichi Oikawa
  • Patent number: 7033685
    Abstract: A method of manufacturing a perpendicular magnetic recording medium, comprises steps of: (a) providing a substrate of an amorphous thermoplastic polymer material having softening and glass transition temperatures as low as about 95° C.; and (b) forming at least one stack of thin film layers atop at least one surface of the substrate, the at least one layer stack including at least one granular magnetic recording layer of perpendicular type, wherein oxides and/or nitrides provide physical de-coupling of adjacent magnetic grains; and wherein each of the thin film layers is formed by depositing at a substrate temperature not greater than about 70° C., and the coercivity (Hc) of the resultant perpendicular magnetic recording medium is at least about 4,000 Oe.
    Type: Grant
    Filed: October 7, 2003
    Date of Patent: April 25, 2006
    Assignee: Seagate Technology LLC
    Inventors: Jean L. Lee, Thomas P. Nolan, Hong Ying Wang, Gary C. Rauch
  • Patent number: 7029772
    Abstract: A magnetic recording medium that enables enhancement of squareness ratio and Hn and exhibits excellent noise characteristics and thermal stability is disclosed. A production process for the medium, and a magnetic recording and reproducing apparatus are also disclosed. The magnetic recording medium including a substrate 1, a carbon-containing carbon undercoat film 2 formed thereon, and a perpendicular magnetic film 3, in which most of easy-magnetization axes are oriented vertically with respect to the substrate, formed on the undercoat film. The perpendicular magnetic film is formed through a plurality of sputtering operations using at least one element selected from Pt and Pd and through a plurality of sputtering operations using a Co-containing material.
    Type: Grant
    Filed: September 10, 2001
    Date of Patent: April 18, 2006
    Assignee: Showa Denko Kabushiki Kaisha
    Inventors: Hiroshi Sakai, Tetsuya Osaka
  • Patent number: 6994923
    Abstract: A magnetic recording medium in which the medium noise is reduced and information can be recorded at a high S/N level, and a method for producing the magnetic recording medium are provided. A magnetic recording apparatus, which is excellent in thermal stability and which makes it possible to perform the high density recording, is provided. When films are formed for the magnetic recording medium based on the perpendicular magnetic recording method, the content of B in a seed layer is made sufficiently larger than the content of B in a recording layer. Accordingly, B is diffused from the seed layer to the recording layer to facilitate the segregation of B at the crystal grain boundary in the recording layer. Thereby, the magnetic interaction between the crystal grains in the recording layer is further reduced. Thus, it is possible to greatly reduce the transition noise.
    Type: Grant
    Filed: June 13, 2003
    Date of Patent: February 7, 2006
    Assignee: Hitachi Maxell, Ltd.
    Inventors: Tetsunori Koda, Akira Yano, Enji Fujita, Tsuyoshi Onuma, Satoshi Matsunuma
  • Patent number: 6972157
    Abstract: A magnetic recording medium comprises a substrate, an undercoat layer, a magnetic layer, and a protective film. The undercoat layer and the magnetic layer are provided atop the substrate. The magnetic layer contains a noble metal layer containing Pt or Pd, a cobalt layer containing Co, and a non-magnetic material layer containing C or Si or Ge.
    Type: Grant
    Filed: March 26, 2003
    Date of Patent: December 6, 2005
    Assignees: Waseda University, Showa Denko Kabushiki Kaisha
    Inventors: Tetsuya Osaka, Hiroshi Sakai