Rare Earth Or Metal Alloy Patents (Class 369/13.45)
  • Patent number: 7423939
    Abstract: A method for manufacturing a magneto-optical recording medium in which reading of recorded information is performed through domain wall displacement in a reproduction layer is provided, in which magnetic separation of groove side-wall portions is performed more reliably; as a result a magneto-optical recording medium with satisfactory recording and reproduction characteristics can be provided.
    Type: Grant
    Filed: February 13, 2004
    Date of Patent: September 9, 2008
    Assignee: Sony Corporation
    Inventors: Takeshi Miki, Kazuhiko Fujiie, Yasuhito Tanaka, Goro Fujita, Tetsuhiro Sakamoto
  • Patent number: 6893746
    Abstract: A magnetic recording medium comprises an information-recording film and a ferromagnetic film on a substrate. The information-recording film is composed of, for example, an amorphous ferrimagnetic material having perpendicular magnetization. Further, the ferromagnetic film is composed of a magnetic material which has saturation magnetization larger than that of the information-recording film. Accordingly, the leak magnetic flux from the ferromagnetic film is larger than that from the information-recording film. The magnetic recording medium and a magnetic recording apparatus are obtained, which are excellent in thermal stability and which are preferred to perform super high density recording.
    Type: Grant
    Filed: October 30, 2000
    Date of Patent: May 17, 2005
    Assignee: Hitachi Maxell, Ltd.
    Inventors: Fumiyoshi Kirino, Norio Ohta, Kouichirou Wakabayashi, Teruaki Takeuchi, Harumi Hieida, Masaki Sekine, Hiroyuki Awano, Akira Yano, Satoshi Matsunuma, Nobuyuki Inaba, Tetsunori Koda
  • Patent number: 6811889
    Abstract: A magneto-optical recording medium including a recording layer for recording information and a substrate for supporting the recording layer is disclosed. The recording layer includes: a recording magnetic film for recording the information, the recording magnetic film being formed of a perpendicular magnetic anisotropy film; and a readout magnetic film for optically reading out the information, the readout magnetic film being capable of being magnetically coupled with the recording magnetic film by an exchange-coupling force. The composition of the readout magnetic film may be chosen such that the exchange coupling force from the recording magnetic film does not affect the magnetization around the surface of the readout magnetic film on the side on which the readout light is incident.
    Type: Grant
    Filed: April 12, 2002
    Date of Patent: November 2, 2004
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Yoshihiko Kudoh, Yasumori Hino, Yuuichi Fukamachi, Masahiro Birukawa
  • Patent number: 6808823
    Abstract: A magneto-optical recording medium including a magnetic recording layer for recording information and a magnetic reproducing layer provided on the magnetic recording layer for reading information. The magnetic reproducing layer is separated into a first reproducing layer having a first composition and a second reproducing layer having a second composition slightly different from the first composition. The first and second reproducing layers have the same principal components. By changing a ratio in film thickness between the first and second reproducing layers, variations in composition of the first and second reproducing layers can be corrected.
    Type: Grant
    Filed: June 13, 2001
    Date of Patent: October 26, 2004
    Assignee: Fujitsu Limited
    Inventors: Tetsuo Hosokawa, Shin-ichiro Matsuo
  • Publication number: 20040196745
    Abstract: A magneto-optical recording medium wherein a magnetic domain is transferred from a recording layer to a reproducing layer is expanded. When the reproducing layer is formed, the composition ratio of a transition metal at a surface of the reproducing layer on a reproducing light beam-incoming side is made to be higher than the composition ratio of the transition metal at a surface of the reproducing layer on a side opposite to the reproducing light beam-incoming side. Thus, the operation to expand the magnetic domain, transferred from the recording layer to the reproducing layer, is performed smoothly, and the jitter of the reproduced signal is reduced to improve signal-to-noise ratio (S/N) of the reproduced signal.
    Type: Application
    Filed: March 26, 2004
    Publication date: October 7, 2004
    Applicant: HITACHI MAXELL, LTD.
    Inventors: Hiroshi Ido, Hiroyuki Awano, Manabu Tani
  • Patent number: 6770387
    Abstract: A magneto-optical recording medium comprising four magnetic layers including a mask layer, a reproduction layer, an intermediate layer and a recording layer, wherein the reproduction layer and the recording layer each have a direction of easy magnetization extending in a layer stacking direction at room temperature, the mask layer and the intermediate layer each have a direction of easy magnetization extending in an in-plane direction at room temperature, the mask layer, the reproduction layer, the intermediate layer and the recording layer have Curie temperatures Tc1, Tc2, Tc3 and Tc4, respectively, which satisfy relationships of Tc3<Tc2, Tc3<Tc4 and Tc3<Tc1, and the intermediate layer is a rare-earth-rich magnetic layer.
    Type: Grant
    Filed: December 5, 2001
    Date of Patent: August 3, 2004
    Assignee: Fujitsu Limited
    Inventors: Tsutomu Tanaka, Motonobu Mihara, Ken Tamanoi
  • Patent number: 6767656
    Abstract: A magneto-optical recording medium comprising four magnetic layers including a mask layer, a reproduction layer, an intermediate layer and a recording layer, wherein the reproduction layer and the recording layer each have a direction of easy magnetization extending in a layer stacking direction at room temperature, the mask layer and the intermediate layer each have a direction of easy magnetization extending in an in-plane direction at room temperature, the mask layer, the reproduction layer, the intermediate layer and the recording layer have Curie temperatures Tc1, Tc2, Tc3 and Tc4, respectively, which satisfy relationships of Tc3<Tc2, Tc3<Tc4 and Tc3<Tc1, and the intermediate layer is a rare-earth-rich magnetic layer.
    Type: Grant
    Filed: March 15, 2001
    Date of Patent: July 27, 2004
    Assignee: Fujitsu Limited
    Inventor: Tsutomu Tanaka
  • Publication number: 20040105348
    Abstract: A magnetic recording medium which includes a first magnetic layer on a substrate is provided with a second magnetic layer having a greater largest possible absolute value of magnetization than the first magnetic layer within a temperature range of from a room temperature to a Curie temperature, and a metal layer made of metal having unspontaneous magnetization property. With this, it is possible to provide a magnetic recording medium having improved coersivity so as to realize stable recording and reproducing even if the size of a record unit is small.
    Type: Application
    Filed: November 24, 2003
    Publication date: June 3, 2004
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Kazuhisa Takayama, Hiroshi Fuji, Jyunichi Satoh, Kunio Kojima, Akira Takahashi
  • Patent number: 6721238
    Abstract: A magneto-optical recording medium for recording and reproducing carriers by laser beam irradiation includes a first magnetic layer which is magnetized in the in-plane direction at room temperature and is perpendicularly magnetized at a predetermined temperature T1 or more; a second magnetic layer which is in contact with the first magnetic layer, has a Curie temperature Tc2 higher than the predetermined temperature T1, and has in-plane magnetic anisotropy up to the Curie temperature Tc2; a third magnetic layer which has a Curie temperature Tc3 higher than the predetermined temperature T1 and has perpendicular magnetic anisotropy at least in a predetermined range of a temperature distribution of the magneto-optical recording medium during laser beam irradiation when reproducing; and a rare earth metal layer formed between the third magnetic layer and the second magnetic layer.
    Type: Grant
    Filed: November 29, 2001
    Date of Patent: April 13, 2004
    Assignee: Sony Corporation
    Inventors: Yasuhito Tanaka, Yoshihiro Muto
  • Patent number: 6671234
    Abstract: A magneto-optical storage medium includes: a reproduction magnetic layer exhibiting in-plane magnetization at room temperature and changing to perpendicular magnetization at a critical temperature or higher; first and second in-plane magnetized layers with Curie temperatures in a proximity of the critical temperature and exhibiting mutually opposite magnetic polarities; and a recording magnetic layer fabricated from a perpendicularly magnetized film, the reproduction magnetic layer, the first and second in-plane magnetized layers, and the recording magnetic layer being sequentially deposited, wherein the reproduction magnetic layer is exchange-coupled with the first and second in-plane magnetized layers at least at room temperature.
    Type: Grant
    Filed: June 28, 2000
    Date of Patent: December 30, 2003
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Junji Hirokane, Noboru Iwata
  • Patent number: 6660404
    Abstract: A magnetooptical recording medium comprising at least a reproduction layer, an intermediate layer, a connection layer and a recording layer, wherein the reproduction layer and intermediate layer have a slant magnetic direction in a non-magnetic field, and the connection layer is composed of a layer non-magnetic at room temperature by itself which is induced to exhibit magnetism by contact with a magnetic layer.
    Type: Grant
    Filed: April 27, 2001
    Date of Patent: December 9, 2003
    Assignee: Fujitsu Limited
    Inventor: Shoyu Ito
  • Patent number: 6638597
    Abstract: In order to improve reproduction characteristics of a magneto-optical recording medium in a case of being subject to a magnetically induced super resolution readout process utilizing a blue-violet laser beam, there is provided a magneto-optical recording medium having a surface roughness of 0.3 nm or less on a surface of a substrate on which recording/reproduction magnetic layers are formed or a surface of a dielectric film formed on the substrate.
    Type: Grant
    Filed: October 26, 2000
    Date of Patent: October 28, 2003
    Assignee: Sony Corporation
    Inventors: Masataka Shinoda, Yasuhito Tanaka, Takashi Shimouma
  • Publication number: 20030189878
    Abstract: At least a reproduction layer of a magneto-optical recording medium is formed by sputtering using a processing gas comprising Kr or Xe as a main component. Hence, it is possible to reduce the dependence of saturation magnetization MS on temperature, thereby decreasing the influence of a demagnetizing field and a floating magnetic field over a wide range of temperature.
    Type: Application
    Filed: April 1, 2003
    Publication date: October 9, 2003
    Inventor: Toshimori Miyakoshi
  • Patent number: 6630252
    Abstract: An MO disk includes a readout layer, an intermediate layer and a recording layer each of which is made of a rare earth-transition metal amorphous material. The MO disk also includes a fourth magnetic layer formed on the recording layer and made of a rare earth-transition metal amorphous magnetic material containing Gd. The fourth magnetic layer has a rare earth metal magnetization-dominant composition and an axis of easy magnetization oriented longitudinally at room temperature. The axis of easy magnetization is changed to be oriented perpendicularly to the fourth magnetic layer as the temperature of the fourth magnetic layer rises to the Curie temperature of the fourth magnetic layer.
    Type: Grant
    Filed: July 28, 2000
    Date of Patent: October 7, 2003
    Assignee: Fujitsu Limited
    Inventor: Toshio Sugimoto
  • Patent number: 6590836
    Abstract: On a dielectric layer of SiN a reproduction layer, a non-magnetic layer of SiN and a recording layer of TbFeCo are formed to provide a magneto optical recording medium. The reproduction layer is formed of a first layer corresponding to a Gd layer, a second layer formed of GdFeCo and a third layer corresponding to a Gd layer. As such, the magneto optical recording medium, with the non-magnetic layer formed in contact with the reproduction layer, can prevent the non-magnetic layer from affecting the reproduction layer and thus prevent the reproduction layer from having a degraded characteristic.
    Type: Grant
    Filed: September 25, 2000
    Date of Patent: July 8, 2003
    Assignee: Sanyo Electric Co., Ltd.
    Inventors: Atsushi Yamaguchi, Hitoshi Noguchi, Hiroki Ishida
  • Publication number: 20030123336
    Abstract: A magneto-optical recording medium for recording and reproducing carriers by laser beam irradiation includes a first magnetic layer which is magnetized in the in-plane direction at room temperature and is perpendicularly magnetized at a predetermined temperature T1 or more; a second magnetic layer which is in contact with the first magnetic layer, has a Curie temperature Tc2 higher than the predetermined temperature T1, and has in-plane magnetic anisotropy up to the Curie temperature Tc2; a third magnetic layer which has a Curie temperature Tc3 higher than the predetermined temperature T1 and has perpendicular magnetic anisotropy at least in a predetermined range of a temperature distribution of the magneto-optical recording medium during laser beam irradiation when reproducing; and a rare earth metal layer formed between the third magnetic layer and the second magnetic layer.
    Type: Application
    Filed: November 29, 2001
    Publication date: July 3, 2003
    Inventors: Yashuhito Tanaka, Yoshihiro Muto
  • Patent number: 6534162
    Abstract: A magneto-optical recording medium includes at least: a reproducing magnetic layer composed at least of Gd and Co showing an in-plane magnetization state at room temperature and a transition to a perpendicular magnetization state at temperatures of not lower than a critical temperature; and a recording magnetic layer formed of a perpendicular magnetization film, the reproducing magnetic layer and the recording magnetic layer being magneto-statically coupled at least in the vicinity of the critical temperature, the reproducing magnetic layer containing at least either Tb or Dy so as to increase the total magnetization at a temperature at which a perpendicular magnetic anisotropy constant and a diamagnetic field energy are equal to each other.
    Type: Grant
    Filed: June 29, 2000
    Date of Patent: March 18, 2003
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Junji Hirokane, Noboru Iwata
  • Patent number: 6521357
    Abstract: A magneto-optical recording medium including a recording layer for recording information and a substrate for supporting the recording layer is disclosed. The recording layer includes: a recording magnetic film for recording the information, the recording magnetic film being formed of a perpendicular magnetic anisotropy film; a readout magnetic film for optically reading out the information, the readout magnetic film being capable of being magnetically coupled with the recording magnetic film by an exchange-coupling force; and a controlling magnetic film, provided between the recording magnetic film and the readout magnetic film, for controlling the exchange-coupling force. The controlling magnetic film has in-plane magnetic anisotropy at room temperature.
    Type: Grant
    Filed: July 10, 2000
    Date of Patent: February 18, 2003
    Assignee: Matsushita Electric Industrial Co,. Ltd.
    Inventors: Yoshihiko Kudoh, Yasumori Hino, Yuuichi Fukamachi, Masahiro Birukawa
  • Publication number: 20020159339
    Abstract: A magneto-optical recording medium is provided with at least: a recording layer, made of a perpendicular magnetization film, in which magnetized information is recorded in the form of a perpendicular direction of magnetization; a magnetic flux generating layer, made of a perpendicular magnetization film, which is exchange-coupled with the recording layer; and a read-out layer, having a perpendicular magnetization at a predetermined temperature or higher temperatures than the predetermined temperature, which copies the magnetized information of the recording layer by magneto-static coupling with the magnetic flux generating layer and the recording layer, wherein the magnetic flux generating layer is a magnetic film having a lower Curie temperature than that of the recording layer and having a larger total magnetization than that of the recording layer at a temperature at which the read-out layer has a perpendicular magnetization.
    Type: Application
    Filed: April 25, 2002
    Publication date: October 31, 2002
    Inventors: Junji Hirokane, Noboru Iwata
  • Patent number: 6430116
    Abstract: A magneto-optical recording medium having a writing layer, a switching layer and a readout layer on a substrate, wherein a magnetization direction corresponding to information is written in the writing layer, and the magnetization direction of the writing layer is transferred to the readout layer by a magnet static coupling force from the writing layer at a temperature of at least room temperature, and wherein the writing layer is composed of a plurality of layers which are made of alloys of a rare earth metal and a transition metal and which are exchange-coupled one another, including a layer having rare earth metal dominant magnetization at room temperature and a layer having transition metal dominant magnetization at room temperature.
    Type: Grant
    Filed: May 5, 2000
    Date of Patent: August 6, 2002
    Assignee: Mitsubishi Chemical Corporation
    Inventors: Toshifumi Kawano, Akio Okamuro