<title>Direct overwriting of magneto-optical disk</title>

Abstract

The possibility of direct overwriting in magneto-optical (MO) disk is demonstrated. By a modfied frequency modulation technique of laser pulse, erasing of recorded bits could be accomplished on the rotating disk. We measured the erasure characteristics for GdTbFe films prepared by RF magnetron sputtering, and found that erasure performance depended on the frequency and the power of the laser pulse and on the magnetic field. We also found that there was an optimum power for erasing the recorded bits. Our experiment produced almost the same rewriting carrier-to-noise ratio (CNR) as the original CNR under a weak constant magnetic field. We confirmed that direct overwriting in MO disk is possible by using a two-beam technique and that read-before-write scheme which makes a drive complex is unnecessary.