Abstract

The direct overwrite technology is one of the most important subjects for achieving a high data transfer rate for the magneto-optical recording system. Several overwrite technologies have been proposed [1]-[3]. The light power modulated overwriting was successfully reported by Saito et al. [2] using an exchange coupled double layer film. It is thought to be the most reliable direct overwrite method, however in addition to a conventinal bias magnet, it needs an initializing magnet which produces a large magnetic field. The initializing magnet makes the drive large and complicated. We have shown the exchange coupled RE-TM quadrilayered film is overwritable with light power modulation using no initializing magnet [4]. This method does not need the initializing magnet because the film has layers which play the same role as the initializing magnet

© 1991 Optical Society of America