| 摘要 |
A perpendicular magnetic recording medium has a magnetic recording layer consisting of two layers. The first magnetic layer, which is a lower layer, comprises crystal grains of a ferromagnetic Co-Cr alloy system and nonmagnetic grain boundaries mainly composed of oxide or nitride, and a thickness a of the first magnetic layer is from 10 nm to 30 nm. The second magnetic layer, which is an upper layer, comprises an amorphous alloy film composed of rare earth element-transition metal alloy, and a thickness b of the second magnetic layer is from 2 nm to 15 nm. The ratio a/b of the thickness a of the first magnetic layer and the thickness b of the second magnetic layer is at least two.
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