Study on readout stability of TbFeCo magneto-optical disks

The authors studied the readout stability of TbFeCo magnetooptical disks by irradiating them with a readout laser beam and found that carrier-to-noise ratio decreases proportionally with the logarithm of time. Thus, the readout stability can be evaluated by determining the log t coefficient. They have found that readout stability is better in transition-metal-rich films than in rare-earth-rich films. Changes in the recorded bit length shows that the carrier-to-noise ratio decreases in proportion to the increase of variance in the recorded bit length