EXCHANGE-COUPLED DOUBLE-LAYERS FOR MAGNETOOPTICAL APPLICATIONS

Optical data storage is a rapidly developing technique, which emerges in many varieties. Magneto-optical recording, in particular, applies a morphous rare earth/transition metal films, where a binary coded infor mation is written thermomagnetically and is read by the magneto-optica l Kerr or Faraday effect. To increase the writing speed and the record ing density, techniques for direct overwrite and magnetically induced superresolution were proposed, which involve these of exchange coupled double layer systems as a storage media. In this paper, the principle s and the properties of exchange coupled double layers are discussed w ith respect to the direct overwrite and the magnetically induced super resolution processes. A formalism based on a switching field diagram i s developed yielding all information necessary to achieve reliable and practical writing procedures. As an example, the direct overwrite cap ability is demonstrated experimentally in antiparallel coupled layer s ystems.