Blue zero field MAMMOS recording

Recently, M. Sekine et al. (Techn. Digest ODS, pp 61, 2001) showed the first experimental results on a new MAMMOS magneto optical super resolution media type, which they call zero-field MAMMOS, that in contrast to the earlier developed AC MAMMOS type can be read-out without the need for any external modulating expansion field. These media were designed for use in a system with a DVD-like optical light path, employing a 650 nm laser and an NA of 0.6. Philips and Hitachi Maxell have, in joint effort, made and tested the first zero field MAMMOS media for use in a first-surface MO (magneto optical) recorder using a blue-violet laser with a wavelength of 405 nm and an NA of 0.7. In this paper we present the first recording results on these media, recorded with an actuated recording head that operates at 15 /spl mu/m from the storage layer of the disc. This distance is an order of magnitude smaller than the free working distance of the Blu-Ray Disc system.