Magneto-optical recording medium and its recording method

Abstract

Abstract PURPOSE:To attain overwriting without complicating the constitution by forming a 2-layer structure perpendicular magnetization film of 1st 2nd magnetic layers each having different Curie point and coercive force satisfying a required condition. CONSTITUTION:A 1st magnetic layer 2 low is Curie point TL and high in coercive force HH and the magnetic layer 3 high in Curie point TH and low in coercive force HL re provided to a transparent base 1 provided with a pre-group, the coercive forces HH, HL are selected to satisfy the following equation to form a magneto-optical disk 35. The layer 3 is magnetized unidirectionally to apply a magnetic field of the strength not inverting the direction of magnetization. Then a bias magnetic field is applied by a recording head 31, then a laser light is used to bring the temperature of the disk 35 to a Curie point TL or TH as the 1st and 2nd kaind of preparatory recordings and in passing the disk through a generating section 34 in such a state, the overwriting constitution such as a 1st kind preparatory recording without modification and different magnetization in a 2nd kind perparatory recording layer 3 is attained without complicated constitution. In equation, Ms is the saturated magnetization of the layer 3, (h) is the thickness of the layer 3 and sigmaw is the magnetized energy between two layers.

Inventors

• 👤 Yoichi Osato
• 👤 陽一 大里
• 👤 一佐哲 河出

Bibliographic Details