Patents by Inventor Charles Leu

Charles Leu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6242086
    Abstract: High areal density magnetic recording media are formed with a thin CoCrTaOx intermediate layer which provides appropriate crystalline orientation and surface morphology for the nucleation and growth of a magnetic layer thereon having increased coercivity and high squareness, while avoiding high substrate heating temperatures. Embodiments include sputter depositing an intermediate layer comprising Co, about 10 to about 20 atomic % Cr and about 1 to about 6 atomic % Ta, at a thickness of about 1.5 to about 18 Å on a Cr or Cr alloy underlayer, allowing partial oxidation of the surface of the intermediate layer by residual oxygen in the sputtering system, and then sputter depositing a CoCrPtTa magnetic alloy layer thereon.
    Type: Grant
    Filed: November 10, 1998
    Date of Patent: June 5, 2001
    Assignee: Seagate Technology LLC
    Inventors: Xing Song, Qixu Chen, Charles Leu, Rajiv Yadav Ranjan
  • Patent number: 6218028
    Abstract: Reproducible texturing of magnetic recording media is enhanced by sputtering a buffer layer, such as Ni—P, on a nonmagnetic substrate, prior to sputtering a textured bump layer. A magnetic recording medium comprising a sputter textured metal layer and high coercivity is achieved by employing an underlayer, such as NiAl or FeAl, preferably a composite underlayer containing a chromium or chromium-alloy layer and a NiAl layer, on the sputter textured layer. Advantageously, the buffer layer, underlayer, textured bump layer, magnetic layer and carbon overcoat can be sputter deposited in a single apparatus.
    Type: Grant
    Filed: March 19, 1998
    Date of Patent: April 17, 2001
    Assignee: Seagate Technology LLC
    Inventors: Xing Song, Ga-Lane Chen, Charles Leu, Qixu Chen
  • Patent number: 6168861
    Abstract: A high areal density magnetic recording medium with high remanent coercivity and high signal-to-noise ratio is formed with dual magnetic layers, the first or lower magnetic layer having a higher saturation magnetization than the second or upper magnetic layer. Embodiments include first and second magnetic layers containing Co and Pt, wherein the first magnetic layer comprises less platinum than the second, e.g., a first magnetic layer of Co15%Cr8%Pt4%Ta and a second magnetic layer of Co15%Cr11%Pt4%Ta.
    Type: Grant
    Filed: November 10, 1998
    Date of Patent: January 2, 2001
    Assignee: Seagate Technology LLC
    Inventors: Qixu Chen, Xing Song, Charles Leu, Rajiv Yadau Ranjan, Ga-Lane Chen
  • Patent number: 6150016
    Abstract: A high areal density magnetic recording medium exhibiting high remanent coercivity and high coercivity squareness is formed with a thin CoCrTa intermediate layer to provide appropriate crystalline orientation and surface morphology for nucleation and growth of a magnetic layer thereon. The present invention also enables the use of lower substrate heating temperatures during deposition. Embodiments include depositing an intermediate Co alloy layer comprising about 10 up to about 15 atomic % Cr and about 1 to about 6 atomic % Ta at a thickness of about 1.5 to about 150 .ANG..
    Type: Grant
    Filed: November 10, 1998
    Date of Patent: November 21, 2000
    Assignee: Seagate Technolgy, Inc.
    Inventors: Xing Song, Qixu Chen, Charles Leu, Rajiv Y. Ranjan
  • Patent number: 6146754
    Abstract: A high areal density magnetic recording medium exhibiting high Hc, high SNR, high S* and substantially isotropic magnetic properties is achieved by depositing a thin seedlayer before depositing the underlayer. Embodiments include heating the seedlayer under vacuum in the presence of residual oxygen to induce appropriate crystalline orientation and surface morphology for nucleation and growth of the underlayer and magnetic layer having substantially isotropic magnetic properties.
    Type: Grant
    Filed: September 2, 1998
    Date of Patent: November 14, 2000
    Assignee: Seagate Technology, Inc.
    Inventors: Xing Song, Qixu Chen, Charles Leu, Rajiv Yadav Ranjan
  • Patent number: 6139951
    Abstract: A magnetic recording medium exhibiting high remanent coercivity and low noise is produced by depositing a first NiAl seedlayer on a non-magnetic substrate, e.g., glass, ceramic or glass-ceramic material, at a relatively low temperature, and subsequently depositing a second NiAl seedlayer on the first seedlayer at a relatively higher temperature. Embodiments include depositing a first NiAl seedlayer at a temperature less than about 120.degree. C., e.g., less than about 100.degree. C., and depositing a second NiAl seedlayer thereon at a temperature greater than about 200.degree. C., e.g. greater than about 230.degree. C. Embodiments also include depositing a Cr-alloy underlayer, CrV, on the second seedlayer.
    Type: Grant
    Filed: November 10, 1998
    Date of Patent: October 31, 2000
    Assignee: Seagate Technology LLC
    Inventors: Qixu Chen, Xing Song, Charles Leu, Rajiv Ranjan
  • Patent number: 6139981
    Abstract: Adhesion between a deposited seed layer, e.g., a sputter-deposited NiP seed layer, on an alternate substrate, such as a glass, ceramic or glass-ceramic substrate, is significantly enhanced by depositing a chromium or chromium-alloy adhesion enhancement film between the substrate and seed layer. Magnetic recording media comprising a surface-oxidized NiP seed layer and chromium adhesion enhancement film exhibit low media noise and are suitable for high density longitudinal magnetic recording.
    Type: Grant
    Filed: September 14, 1998
    Date of Patent: October 31, 2000
    Assignee: Seagate Technology, Inc.
    Inventors: Elsie Yang Chuang, Phuong Nguyen, Qixu David Chen, Xing Song, Charles Leu, Thanh Thien Ha
  • Patent number: 6132863
    Abstract: Simultaneous crystallographic orientation and grain size refinement of the magnetic layer are achieved by depositing a grain size control layer on a underlayer. Embodiments include depositing a CrV grain size control layer on a Cr underlayer at thickness ratio of underlayer to grain size control layer of about 0.5 to about 2. Magnetic layers having a grain size of about 100 .ANG. to about 250 .ANG., e.g. at 180 .ANG. to about 220 .ANG., are achieved.
    Type: Grant
    Filed: September 24, 1998
    Date of Patent: October 17, 2000
    Assignee: Seagate Technology LLC
    Inventors: Xing Song, Qixu Chen, Charles Leu, Rajiv Y. Ranjan
  • Patent number: 6120890
    Abstract: A glass or glass-ceramic substrate comprising about 0.5 to about 32 wt. % Li.sub.2 O is employed as a non-magnetic substrate of a magnetic recording medium. Migration of Li from the substrate to the medium's surface is prevented by forming an amorphous NiP sealing layer on the substrate, with an optional adhesion enhancement layer therebetween. Embodiments include surface oxidizing the amorphous NiP sealing layer for enhanced recording performance.
    Type: Grant
    Filed: November 5, 1998
    Date of Patent: September 19, 2000
    Assignee: Seagate Technology, Inc.
    Inventors: Qixu Chen, Xing Song, Liji Huang, Charles Leu, Rajiv Ranjan
  • Patent number: 6117570
    Abstract: High areal density magnetic recording media exhibiting low noise are formed with a surface oxidized NiAl seed layer. Embodiments include forming the surface oxidized NiAl seed layer on a glass or glass-ceramic substrate, and sequentially depositing a Cr or Cr-alloy, such as CrV, an intermediate CoCrTa layer and a CoCrPtTa magnetic layer.
    Type: Grant
    Filed: September 14, 1998
    Date of Patent: September 12, 2000
    Assignee: Seagate Technology, Inc.
    Inventors: Qixu David Chen, Liji Huang, Charles Leu, Rajiv Yadav Ranjan
  • Patent number: 6010795
    Abstract: A magnetic recording medium is formed by depositing a Cr-containing sub-underlayer on a surface oxidized seed layer, such as NiP, with direct current (DC) magnetron sputtering, depositing a NiAl or FeAl underlayer on the sub-underlayer, and depositing a Cr-containing intermediate layer on the NiAl or FeAl underlayer. The medium features high coercivity, low noise, and (200)-dominant underlayer crystallographic orientation, even with sub-underlayer deposition at temperatures as low as about 25.degree. C. The medium is suitable for high density longitudinal magnetic recording.
    Type: Grant
    Filed: October 17, 1997
    Date of Patent: January 4, 2000
    Assignee: Seagate Technology, Inc.
    Inventors: Qixu Chen, Jyh-Kau Chang, Charles Leu, Ga-Lane Chen