Temperature Or Coercivity Patents (Class 369/13.51)
  • Patent number: 9373356
    Abstract: According to one embodiment, a magnetic recording and reproducing device includes a magnetic recording medium, a recording unit, and a reproducing unit. The magnetic recording medium includes a first track including first and second sub-tracks extending in a first direction. The second sub-track is arranged with the first sub-track in a second direction intersecting the first direction. The recording unit records information in the first and second sub-tracks. The reproducing unit reproduces the information recorded in the first and second sub-tracks while opposing the first, second sub-tracks, and a boundary between the first and second sub-tracks. The first sub-track includes first magnetic recording components including first and second components. The second sub-track includes second magnetic recording components including third and fourth components. A first recording symbol is formed of the first and third components. A second recording symbol is formed of the second and fourth components.
    Type: Grant
    Filed: October 20, 2015
    Date of Patent: June 21, 2016
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kenichiro Yamada, Masayuki Takagishi, Tomoyuki Maeda, Yousuke Isowaki, Naoyuki Narita, Shuichi Murakami
  • Patent number: 8885447
    Abstract: An aspect of the present invention relates to glass for a magnetic recording medium substrate, which comprises essential components in the form of SiO2, Li2O, Na2O, and one or more alkaline earth metal oxides selected from the group consisting of MgO, CaO, SrO, and BaO wherein a molar ratio of a content of CaO to a combined content of MgO, CaO, SrO, and BaO (CaO/(MgO+CaO+SrO+BaO)) is equal to or less than 0.20, and which has a glass transition temperature of equal to or higher than 650° C.
    Type: Grant
    Filed: March 15, 2013
    Date of Patent: November 11, 2014
    Assignee: Hoya Corporation
    Inventors: Naomi Matsumoto, Kazuaki Hashimoto
  • Patent number: 8879376
    Abstract: Provided are an optical information recording medium and an optical information recording device that enable to accurately form recording marks each having a certain code length and to accurately reproduce information, even in the case where shingled write recording is applied to optical information recording. An optical information recording medium (1) is provided with a user area (102) configured such that optical characteristics of a photosensitive recording material are changed by irradiation of laser light for recording information. The user area (102) includes recording tracks (104) on which information is recorded by overwriting a part of recording marks (106), and a heat insulating area (105) which is concentrically or spirally formed, and insulates heat generated by irradiation of the laser light. The heat insulating area (105) is formed between the recording tracks (104).
    Type: Grant
    Filed: February 20, 2012
    Date of Patent: November 4, 2014
    Assignee: Panasonic Corporation
    Inventor: Kenji Narumi
  • Patent number: 6844083
    Abstract: A magneto-optical recording medium has a configuration such that information recorded can be read from a region smaller than a beam spot by applying an external magnetic field and directing a light beam in reproducing. The magneto-optical recording medium includes a magnetic recording layer for recording and holding information, a magnetic reproducing layer provided on one side of the magnetic recording layer on which the light beam is incident, a nonmagnetic layer provided on another side of the magnetic recording layer opposite to the magnetic reproducing layer, and a magnetic assist layer provided on the nonmagnetic layer. The magnetic assist layer has a coercive force smaller than an external magnetic field applied in recording or reproducing information.
    Type: Grant
    Filed: July 29, 2003
    Date of Patent: January 18, 2005
    Assignee: Fujitsu Limited
    Inventors: Toshio Sugimoto, Ken Tamanoi
  • Patent number: 6802073
    Abstract: Disclosed are magneto-optical recording media including at least a reflection layer, a recording layer and a dielectric layer laminated on a substrate in this order, wherein the thickness of the dielectric layer is not less than 140 nm or wherein the dielectric layer is provided by the lamination of upper dielectric layer and lower dielectric layer in which the thermal conductivity of the upper dielectric layer is higher than that of the lower dielectric layer. By arranging the thickness of the dielectric layer in a specific range, the surface roughness of a media in not more than 1.5 nm, and providing a reflection layer composed of a noble metal alloy, achieved is a magneto-optical recording medium able to record constantly in near-field magneto-optical recording, suitable for narrow track pitch, and having excellent SNR, resolution, and recording sensitivity.
    Type: Grant
    Filed: April 29, 2003
    Date of Patent: October 5, 2004
    Assignee: Tosoh Corporation
    Inventors: Koyata Takahashi, Toshio Inase, Keiichiro Nishizawa
  • Patent number: 6377414
    Abstract: Patterned magnetic media are provided at high resolution and pattern definition by a process comprising steps of: applying to a magnetic layer a first uniform magnetic field of a first direction and strength to pre-align the magnetic grains thereof; applying a second uniform magnetic field of a second, opposite direction and of lesser strength than the first magnetic field, sufficient to change the alignment of the magnetic grains only when the temperature thereof is equal to or greater than the Curie temperature Tc; selectively increasing the temperature of a pattern of selected surface areas of the magnetic layer to at least Tc for an interval while applying the second magnetic field to thereby selectively change the alignment of the magnetic grains of the selectively heated surface areas; terminating application of the second magnetic field after completion of the selective realignment; and cooling the selectively heated surface areas to a temperature below Tc, whereby the magnetic pattern is preserved in
    Type: Grant
    Filed: November 9, 2000
    Date of Patent: April 23, 2002
    Assignee: Seagate Technology LLC
    Inventor: Li-Ping Wang
  • Publication number: 20010050885
    Abstract: A magneto-optical recording medium includes a reproducing layer. When a laser beam is irradiated to the magneto-optical recording medium, a magnetic domain in a recording layer is transferred, through enlargement, to a reproducing layer increased in temperature. The magneto-optical recording medium further includes a calibration area that has a calibration magnetic domain recorded in a predetermined pattern in the recording layer. In a reproducing apparatus, a laser beam of an optical head is adjusted in output depending upon a reproduced signal obtained by reproducing the calibration magnetic domain.
    Type: Application
    Filed: August 17, 2001
    Publication date: December 13, 2001
    Applicant: Sanyo Electric Co., Ltd
    Inventors: Atsushi Yamaguchi, Naoyuki Takagi, Yoshiharu Uchihara, Satoshi Sumi, Hiroyuki Awano, Hiroshi Shirai, Hitoshi Watanabe, Norio Ohta