| 摘要 |
PROBLEM TO BE SOLVED: To suppress increase in manufacturing cost of a magneto-optical recording medium and a device for recording on the medium by eliminating the need for aligning the magnetization of a magnetic layer to one direction by a large magnetic field or high laser power prior to shipping from a factory or prior to recording while making optically modulated overwriting possible. SOLUTION: The Curie points of the first magnetic layer 3, second magnetic layer 4, third magnetic layer 5 and fourth magnetic layer 6 of a rare earth transition metal allay of a ferrimagnetic material exhibiting perpendicular magnetization from room temp. to the Curie point are respectively defined as Tc1, Tc2, Tc3, Tc4. Room temp.<Tc3<Tc4<Tc1<Tc2 are then obtd. If the respective auxiliary lattice magnetizations of the transition metal and rare earth metal are respectively defined asα,β, the second magnetic layer 4 is more dominant inαthanβat Tc1 to Tc2 and the fourth magnetic layer 6 is more dominant inβthanαfrom room temp. to Tc4.
|
