| 摘要 |
In a granular magnetic recording layer of a perpendicular magnetic recording medium, media noises are reduced by separating adequately magnetic crystal grains and non-magnetic grain boundary and decreasing magnetic exchange interactions among the magnetic crystal grains without causing damage to magnetic anisotropy of the magnetic crystal grains. In one embodiment, the perpendicular magnetic recording medium, in which crystal alloy grains containing Co, Pt, and Cr, and non-magnetic grain boundary containing Si and O is included; the ratio of the number of O atom to that of Si atom in the magnetic recording layer is between about 2.5 and 5; the Si atomic composition in the magnetic recording layer is between about 3 and 6 atomic %; and the O atomic composition in the magnetic recording layer is between about 12 and 20 atomic %, is used. The in-plane distribution of perpendicular coercivity at any points of the medium of the magnetic recording layer is made at most about ±10% of an average value.
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