| 摘要 |
A perpendicular magnetic recording medium, which suppresses generation of spike noises, has a soft magnetic backing layer constructed of a laminated structure. The backing layer has at least one nonmagnetic metal layer at most 5 nm thick and at least two soft magnetic layers each at least 10 nm thick being alternately laminated, with the top layer and the bottom layer being the soft magnetic layers. The nonmagnetic metal layer is composed of a metal selected from Cu, Ru, Rh, Pd, Re, Os, Ir, Pt, and Au, or an alloy of these metals. The directions of magnetization in the two soft magnetic layers sandwiching the nonmagnetic metal layer are parallel to the plane of the soft magnetic layer and different from each other by 180 degrees, and the two soft magnetic layers are antiferromagnetically coupled. This structure prevents formation of magnetic domain walls when an external magnetic field is applied, thus suppressing spike noises.
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