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 μm 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 μm (0.2 μm/bit). We have also verified that marks as short as 0.12 μm long are recorded, although the S/N is insufficient