In this paper we propose a new method to reproduce signals from high-density recorded patterns irrespective of the resolution of the readout optical system. The basic mechanism of this method, that is, domain wall displacement due to the temperature gradient, was confirmed by direct observation through a polarizing microscope. A clear readout waveform and a CNR of 39.5dB were obtained for a mark length of O.l,um with this method.

Magnetic and magneto-optical properties, Ken rotation angle, Kerr ellipticity and reflectance, were investigated for Pt substituted MnSb compound films with film thickness of about 1OOObi by RF sputtering in the concentration range of 44at%cMn45at%, 37at%

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We realized acceptable read/write performances at a track pitch of 320 nm and a bit length of 75 nm, even with an NA of 0.65 and a wavelength of 405 nm, using side-wall-annealing. In addition to this result, we suggested the possibility of a higher linear density; that is, a jitter value of less than 15% was obtained both on land and in groove at a bit length of 60 nm, which corresponds to an areal density of 34 Gbit/in 2 .

High-density recording four times that of a current DVD-RAM has been achieved by applying Domain Wall Displacement Detection (DWDD) technology using a conventional optical head which has the same wavelength of 660 nm and NA of 0.6 as the DVD head. It has been confirmed by using a sampled servo and PRML that a recording density of 15 Gbit/inch2 with a track pitch of 540 nm and bit length of 80 nm has sufficient system margin. This means that a capacity of 3 GB on a two-inch-diameter disk is now available for portable use. If applied to a digital video camera, one hour of MPEG2 video contents can be recorded at a transfer rate of 6 Mbps.