Invention Grant
- 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
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Application No.: US12678086Application Date: 2008-09-30
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Publication No.: US08367229B2Publication 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

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.
Public/Granted literature
- US20100246060A1 PERPENDICULAR MAGNETIC RECORDING MEDIUM AND MAGNETIC RECORDING AND REPRODUCING APPARATUS Public/Granted day:2010-09-30
Information query
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