| 摘要 |
PROBLEM TO BE SOLVED: To provide a magnetic recording disk used for magnetic recording and reproducing method effective for holding the secrecy of the data signals recorded at a magnetic layer. SOLUTION: The magnetic recording disk is constituted by laminating a magnetic layer for recording the data signals and a recording layer for recording dummy signals on a nonmagnetic base. The magnetic layer for recording the data signals is a high-coercive force magnetic material layer which is formed by using ferromagnetic metallic powder of 35 to 85 m2/g in specific surface area or hexagonal ferrite powder of 10 to 200 m2/g in specific surface area as magnetic powder and having coercive force of 1500 to 2500 oersted and a layer thickness of 0.3 to 3.0μm and the recording layer for recording the dummy signals is a low-coercive force magnetic material layer which is formed by using magnetic powder having a specific surface area smaller than the specific surface area of the magnetic powder of the high-coercive force magnetic material layer and has coercive force of 200 to 1000 oersted and a layer thickness of 0.03 to 0.20μm. The center line average roughness of the coercive force magnetic material layers is <=10 nm.
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