PHOTOMAGNETIC RECORDING MEDIUM FOR COMPENSATION POINT WRITING

• Main Authors: KIMURA FUMITO, AKASAKA HIDEKI
• Format: Patent
• Language: English
• Published: 05.09.1985
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRICITY; INDUCTANCES; INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; MAGNETS; PHYSICS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES; TRANSFORMERS

PURPOSE:To obtain a photomagnetic recording medium for compensation point writing having high S/N by providing Fe and Co which are transition metals and Dy, Tb, Gd which are rare earth metals in such a way that the magnetic moments of the transition metals and the rare earth metals are reversed in the upper and lower layers. CONSTITUTION:An amorphous vertical magnetized film a consisting of Gd15Tb2Fe52Co31 is formed, for example, in the lower part of a substrate in a way as to have a high Curie temp. TA and high Kerr rotating angle theta by using, for example, a high-frequency three-dimensional magnetron sputtering device and by placing a Tb or Dy chip on a Gd disk for one target and placing a Co disk and Fe disk on the other two targets and changing the compsn. ratio of (GD+ Tb or Dy):Fe:Co. An upper amorphous vertical magnetized film B consisting of Gd21Tb2Fe45Co29 and having a high Curie temp. TB is formed thereon to manufacture a photomagnetic recording medium. Writing is performed on such medium at the temp. below the temps. TA, TB. (Such writing is called compensation point writing.) The recording medium which records the vertical magnetized film with signals 0, 1 in the form of upward and downward magnetization and has a good S/N is thus obtd.