Recording Characteristics of Magneto-Optical Disk with Quadrilayer Structure

The effects of recording sensitivity and recording conditions on bits recorded on sputtered four-layer GdTbFe film are reported. A correlation was seen between recorded bit length and film optical absorption per unit thickness. As films were made thinner, the resulting bit length grew longer and the film became more sensitive. Fluctuation in bit widths was minimum at a recording power of 5.1 mW and a bias field strength of 500 to 600 Oe. The bit size was determined by the film temperature and coercive force, the bias field, and the temperature gradient in the medium. For 4/5 modulation, the shortest bit length was approximately 1.3 ¿m.