Magneto-optical media

Abstract

The present invention relates to a magneto-optical media. More particularly, the present invention relates to a device for assuring a high S/N ratio by controlling the optical phase difference of the media by optimizing the film structure of a multi-layered thin film. The structure of the multi-layered thin film is such that the first protective film of a thickness between 400 .ANG. and 700 .ANG., a recording film of a thickness between 150 .ANG. and 300 .ANG., the second protective film of a thickness between 150 .ANG. and 250 .ANG., and a reflecting film of a thickness between 400 .ANG. and 800 .ANG., are successively laminated on a substrate. The first protective layer and the second protective layer are both suitably made of AlSiN, SiN, or SiO.sub.2 having refractivity between 1.95 and 2.05. The recording layer has a composition: Nd.sub.x Dy.sub.y (FeCo).sub.100-x-y, or Nd.sub.x (DyTb).sub.y (Fe.sub.1-z Co.sub.z).sub.100-x-y, where 25 at %.ltoreq.x+y.ltoreq.30 at %, 0 at %.ltoreq.x.ltoreq.8 at %, and 0.07 at %.ltoreq.z.ltoreq.0.43 at %.

Dependencies are inferred from the claim text.