MAGNETOOPTICAL RECORDING MEDIA.

摘要

A magnetooptical recording medium comprises a transparent substrate (10), on which are sequentially laminated a protective film (14); a first magnetic film (11) made of a light rare earth metal, heavy rare earth metal, and transition metal alloy; a second magnetic film (12) made of a light rare earth metal, heavy rare earth metal, and transition metal alloy; a third magnetic film (13) made of a light rare earth metal, heavy rare earth metal, and transition metal alloy; a protective film (15); and a reflecting film (16). The sandwich of the first, second and third magnetic layers constitutes a recording film (17). The compositions of the first and third magnetic layers contain a large amount of light rare earth metal and have a large Kerr rotational angle in a single wavelength region (400 nm to 700 nm). On the other hand, the composition of the second magnetic layer contains a large amount of heavy rare earth metal and has a property suitable for vertical magnetization. The recording film (17) consisting of the sandwich of the first, second and third magnetic layers has a large Kerr rotational angle as a whole in a short wavelength region, and has a large coercive force. This recording film (17) is sufficiently thin (below 400 ANGSTROM ). When the three-layered sandwich and the reflecting layer (16) are combined with each other, a further greater Kerr rotational angle can be obtained.