| 摘要 |
PURPOSE:To obtain the recording medium which decreases modulation by successively laminating at least two layers of sputtered layers of thin chromium films having bow-shaped columnar structures, the sputtered layer of a thin magnetic alloy film and a thin protective film on a nonmagnetic substrate. CONSTITUTION:Ni-P is plated on the Al alloy substrate 11 and thereafter, the surface thereof is polished and textured. The thin Cr films 25 are formed of the Cr layer 12 having the 1st bow-shaped columnar structure projecting in the transporting direction of the substrate 11, the Cr layers 13, 14 having the 2nd, 3rd bow-shaped columnar structures and the thin magnetic film 26 and the protective layer 17 are provided thereon. The substrate 11 is transported in a direction 22 at the time of film formation. The curvature (r) of the bow-shaped columnar layers 12, 13, 14 is specified to about 240nm and the thickness t of the respective layers to about 130nm. The value of r/t in this case is about 1.8. The r/t is about 1 in case of one layer of the thin Cr film consisting of the bow-shaped columnar structure. The columnar structures grow more perpendicularly to the substrate surface as the value of the r/t is larger and, therefore, the magnetic anisotropy in the substrate transporting direction of the magnetic recording medium is decreased and the coercive force Hc uniform in the circumferential direction of the disk is applied. The recording medium which decreases the modulation is thus obtd. |
