Manufacturing method for magneto optical recording medium

Abstract

A magneto optical recording medium capable of stable recording and readout using a DWDD system is provided. The magneto optical recording medium of the present invention comprises an optical disk substrate and a multilayer recording film comprising essentially a readout layer, an intermediate layer, and a recording layer successively formed on top of the substrate. The readout layer has a smaller magnetic domain wall coercivity than the recording layer. The intermediate layer comprises a magnetic layer whose Curie temperature is lower than the readout layer and the recording layer. A recorded/readout magnetic domain corresponding to recorded/readout information is formed only in a groove area of the optical disk substrate. The thickness of the recording film at the boundary between mutually adjacent recording track areas is smaller than the thickness of the recording film in the center portions of the recording track areas.

1 . A manufacturing method for magneto optical recording medium comprising an optical disk substrate and a multilayer recording film comprising essentially a readout layer, an intermediate layer, and a recording layer successively formed on top of said optical disk substrate, said manufacturing method comprising the steps of: 
 placing within a vacuum chamber, a target and said optical disk substrate in a position opposite said target, said target being made of a material having a composition for forming said recording film, and    forming the recording film by magnetron-sputtering the target onto said optical disk substrate while holding said substrate stationary or rotating said substrate on its axis without moving the center of said optical disk substrate.    
     
     
         2 . A manufacturing method for a magneto optical recording medium according to  claim 1 , wherein in the step of forming the recording film, the recording film is formed by magnetron-sputtering a plurality of said targets.  
     
     
         3 . A manufacturing method for a magneto optical recording medium according to  claim 1 , wherein the material having the composition for forming said recording film is an alloyed material.  
     
     
         4 . A manufacturing method for a magneto optical recording medium according to  claim 1 , wherein in the step of forming the recording film, a sputtering area of the target is limited.  
     
     
         5 . A manufacturing method for a magneto optical recording medium according to  claim 1 , wherein a principal ingredient of a sputtering particle from the target enters said optical disk substrate perpendicularly.