Perpendicular magnetic recording medium
First Claim
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1. An apparatus comprising:
- a substrate; and
a recording section supported by the substrate comprising first and second ferro-magnetic layers and a non-magnetic layer, said first layer disposed between the substrate and the second layer and having a perpendicular magnetic anisotropy energy (Ku) greater than that of the second layer and a saturated magnetization (Ms) value greater than 500 emu/cc, the recording section having an overall saturated magnetization (Ms) value equal to or greater than 1000 emu/cc and having an overall perpendicular magnetic anisotropy energy (Ku) equal to or greater than 9×
106 erg/cc.
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Abstract
A perpendicular type of magnetic recording medium has a multi-layered recording structure made up of a plurality of ferro-magnetic layers and a non-magnetic layer interposed between the plurality of ferro-magnetic layers, and the perpendicular magnetic anisotropy energy of the lower ferro-magnetic layer is greater than the perpendicular magnetic anisotropy energy of the upper ferro-magnetic layer. Accordingly, the lower ferro-magnetic layer may be easily magnetically reversed by a magnetic field applied during a write operation. Thus, the perpendicular type of magnetic recording medium exhibits an enhanced thermal stability and write-ability.
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15 Claims
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1. An apparatus comprising:
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a substrate; and a recording section supported by the substrate comprising first and second ferro-magnetic layers and a non-magnetic layer, said first layer disposed between the substrate and the second layer and having a perpendicular magnetic anisotropy energy (Ku) greater than that of the second layer and a saturated magnetization (Ms) value greater than 500 emu/cc, the recording section having an overall saturated magnetization (Ms) value equal to or greater than 1000 emu/cc and having an overall perpendicular magnetic anisotropy energy (Ku) equal to or greater than 9×
106 erg/cc. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An apparatus comprising:
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a substrate; and a recording section supported by the substrate comprising first, second and third ferro-magnetic layers and a non-magnetic layer between the first and third layers, the first layer disposed between the substrate and the second layer, the first layer having a saturated magnetization (Ms) value greater than 500 emu/cc and a perpendicular magnetic anisotropy energy (Ku) from 5×
106 erg/cc to 5×
107 erg/cc, each of the first, second and third layers formed of a common material with magnetic grains having an average size equal to or smaller than 9 nm. - View Dependent Claims (13, 14, 15)
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Specification