| 摘要 |
PURPOSE:To obtain a photomagnetic recording medium satisfying both the signal quality and productivity with high density and high reliability by laminating >=3 magnetic layers via a nonmagnetic layer and specifying the total of the film thickness of each magnetic layer. CONSTITUTION:A background layer 17 is provided to a substrate 1, a nonmagnetic layer 14 and a magnetic layer 13 are laminated alternately on the layer 17 and an over coat 18 is provided further on the layer 13. The minimum film thickness 15 of the magnetic layer 13 is 200Angstrom by the present film forming technology, and the upper limit of the film layer depends on the film forming speed and the productivity or the like, nearly 5mum to the utmost. It is required to provide >=3 layers for the number of lamination of the magnetic layers 13. Assuming the recording laser power P as P1-P3 (P1<P2<P3), then the relation between the recorded bit diameter and the number of lamination of magnetic layers with a constant pulse width is shown in the figure, that is, the recording sensitivity is increased as the number of lamination increases and when >=3 layers are adopted, the result starts to show its effect remarkably. |
