Abstract

MO technology is now widely used for erasable optical storage. Almost all MO media products to date are based on rare-earth/transition metal alloys (RE-TM), such as TbFeCo. Although these alloys provide excellent recording performance, their intrinsic corrosion sensitivity necessitates the use of protective layers, typically thin nitride films, on both sides of the recording layer, to protect them from the environment. Frequently, to further enhance the recording performance, an additional reflector layer is used to form an optically tuned quadri-layer structure. The nitride type protective layers are slow and difficult to fabricate. The multilayer, optically tuned structure necessitates tight manufacturing tolerance. The compatibility between layers in terms of adhesion and stress often is difficult to control. These factors, and the fact that the RE-TM alloys are sensitive to oxidation and need to be coated in an excellent vacuum environment, all contribute to the cost of the media.

© 1996 Optical Society of America