Norio Miyatake

MSR and land/groove recording combined

This paper describes the combining of MSR and land/groove recording. The combination of MSR and shallow groove type land/groove recording gives excellent results. Double mask type MSR has the advantage of limiting crosstalk, regardless of type of shallow groove. At narrow track pitches, cross-erasing is a greater problem than crosstalk. We attempted a pulse train erasing method to reduce cross-erasing. As a result, an erasing power allowance of /spl plusmn/20% was achieved with a track pitch of 0.65 /spl mu/m using a NA0.55 magneto-optical head with a LD wavelength of 680 nm.

MSR high density recording

This paper describes the high density recording using magnetically induced super resolution (MSR). We have used the double mask type of MSR, which consists of four layers of magnetic film. Recording and readout were performed with an optical head with a wavelength of 680 nm and NA 055. With light intensity modulation (LIM) recording, the lower limit of the mark length is approximately 0.35 /spl mu/m because the limit of recording density is restricted by the recording power margin. With magnetic field modulation (MFM) recording combined with laser pulse, however, the recording power margin increases considerably, and recording density can be increased to the limit of S/N. We have performed MFM recording with NRZi modulation, under the assumption that a modulation method with a wide data window is adequate for MSR even when the shortest mark shrinks proportionally. Our results confirm the possibility of high density recording with marks as short as 0.2 /spl mu/m (0.2 /spl mu/m/bit). We have also verified that marks as short as 0.12 /spl mu/m long are recorded, although the S/N is insufficient.

Magnetically-induced super resolution for read only memory disks

Recently, a magnetically-induced super resolution for read only memory disks (MSRROM), which utilizes the difference in coercivity between ‘’rough’’ and “smooth” areas in a disk has been proposed [l]. A double mask type MSR with high-resolulion for readout is realized. This method is advantageous for replication and for the compatibility with rewritable magnetooptical recording. This paper describes the recording performance in the MSR-ROM.

New Msr Method for High Density Read Only Disks

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