Invention Grant
US08367229B2 Perpendicular magnetic recording medium and magnetic recording and reproducing apparatus 有权
垂直磁记录介质和磁记录和再现装置

  • Patent Title: Perpendicular magnetic recording medium and magnetic recording and reproducing apparatus
  • Patent Title (中): 垂直磁记录介质和磁记录和再现装置
  • Application No.: US12678086
    Application Date: 2008-09-30
  • Publication No.: US08367229B2
    Publication Date: 2013-02-05
  • Inventor: Yuzo Sasaki
  • Applicant: Yuzo Sasaki
  • Applicant Address: JP Tokyo
  • Assignee: Showa Denko K.K.
  • Current Assignee: Showa Denko K.K.
  • Current Assignee Address: JP Tokyo
  • Agency: Sughrue Mion, PLLC
  • Priority: JP2007-259306 20071003
  • International Application: PCT/JP2008/067744 WO 20080930
  • International Announcement: WO2009/044733 WO 20090409
  • Main IPC: G11B5/66
  • IPC: G11B5/66
Perpendicular magnetic recording medium and magnetic recording and reproducing apparatus
Abstract:
The present invention relates to a perpendicular magnetic recording medium including a nonmagnetic substrate, and at least a soft magnetic layer (SUL), an alignment control layer, a magnetic recording layer and a protective layer formed on the nonmagnetic substrate, wherein the magnetic recording layer is constituted of two or more layers and includes a first magnetic recording layer and a second magnetic recording layer from the nonmagnetic substrate side and, regarding magnetocrystalline anisotropic energy Ku of each magnetic recording layer, the first magnetic recording layer has 4×106 erg/cc or higher and the second magnetic recording layer has 2×106 erg/cc or lower, wherein the first magnetic recording layer is constituted of CoCrPtRu magnetic alloy crystal grains and grain boundaries made of an oxide and the area of grain boundaries is 30% or more based on the entire area in a planar TEM observation of the first magnetic recording layer. The present invention also relates to a magnetic recording and reproducing apparatus using the perpendicular magnetic recording medium.
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