| 摘要 |
PURPOSE:To improve the reproduction characteristic of information by forming six layers on a transparent substrate with a prescribed composition and thickness, i.e., a photomagnetic recording medium film, garnet magnetic film, photomagnetic recording medium film, metallic reflection layer and a dielectric substance layer. CONSTITUTION:A GdTBFe film 16, a Y3Fe5O12 film 17, a GdTBFe film 18, a TiO2 film 19, a Cu reflection film 20 and a TiO2 film 21 are formed on a glass substrate 15 with thickness 50-180Angstrom (e.g., 100Angstrom ), 200-1,200Angstrom (700Angstrom ), 50- 180Angstrom (100Angstrom ), 100-500Angstrom (200Angstrom ), >=200Angstrom (1,000Angstrom ) and >=100Angstrom respectively. If the film 21 is set at >=100Angstrom , the magnetic Kerr revolving angle is set at >=0.7. In this case, however, the film 21 is preferably set at >=2,000Angstrom since the film 21 functions as a protection film. The reproduction characteristics of information can be improved with such film thickness set for each layer. |
