Magnetic Field Modulation Recording on GdDyFeCo Magnetooptical Disk

The characteristics of magnetic field modulation recording on GdDyFeCo magnetooptical disks were investigated. The GdDyFeCo recording layer was deposited by a two-source RF magnetron sputtering method. The thermomagnetic properties of the compositionally modulated films varied with the modulation periodicity, and the recording field (Hs) was smallest at a modulation period of 2 Ã…. On determining the dependence of Hs on the GdDy content, a relatively low Hs was found to appear in the rare earth-rich region near the compensation composition. By optimizing the GdDy content, recording magnetic field transition times of less than 250 ns can be obtained at a recording frequency of 720 kHz.