Hitachi Maxell, Limited

Yoshinori Shirai

Norio Ohta

Hideo Fujiwara

Katsusuke Shimazaki

Eiji Koyama

Masafumi Yoshihiro

Satoru Ohnuki

Yukinori Yamada

Masatoshi Hashimoto

Hitoshi Furusho

Takehiko Yorozu

Noriyuki Ogihara

Disclosed is a magneto-optical recording medium which comprises a transparent substrate and, provided on the substrate, a magneto-optical recording film comprising a perpendicular magnetic film based on rare earth metal-transition metal and an auxiliary magnetic film having spontaneous magnetization which exerts, between itself and the magneto-optical recording film, an exchange coupling force on each other and in which the auxiliary magnetic film used is a magnetic film which readily rotates its magnetization direction toward the external magnetic field in the neighborhood of the Curie temperature of the magneto-optical recording film and has a squareness ratio of not more than 1 in the neighborhood of the Curie temperature, and a process for producing the magneto-optical recording medium.

Magneto-optical recording medium and process for producing the same

Disclosed is a magneto-optical recording medium which comprises a transparent substrate and, provided on the substrate, a magneto-optical recording film comprising a perpendicular magnetic film based on rare earth metal-transition metal and an auxiliary magnetic film having spontaneous magnetization which exerts, between itself and the magneto-optical recording film, an exchange coupling force and wherein the auxiliary magnetic film is a magnetic film which readily rotates its magnetization direction toward the external magnetic field in the neighborhood of the Curie temperature of the magneto-optical recording film and has a squareness ratio of not more than 1 in the neighborhood of the Curie temperature. Also disclosed is a process for producing the magneto-optical recording medium.

A magneto-optic recording medium comprises on a substrate the first dielectric substance layer, a magneto-optic recording layer, the second dielectric substance layer and a reflective layer. The magneto-optic recording layer has, in the range of the Curie temperature Tc to (Tc-50) .degree.C., a value of a product of a saturated magnetization Ms and a coercive force Hc of not more than 4.times.10.sup.4 erg/cm.sup.3. The magneto-optic recording medium can be recorded at a magnetic field as low as 100 (Oe) with an excellent C/N.

Magneto-optical recording medium having multiple magnetic layers for

Growing community of inventors

Ibaraki-ken, Japan

Yoshinori Shirai