System tolerance of 64-mm-diameter magneto-optical disks with a 4.7-Gigabyte capacity

Anneal-Less Domain Wall Displacement Detection of 27 Gbit/in2 Land/Groove Recording Using a Deep Groove Substrate and a Blue Laser

“…We prepared deep groove substrates using a stamper formed by reactive ion etching (RIE) and O 2 plasma treatment to smooth the groove surfaces. 4) The surface roughness on the land and in the groove was less than 0.4 nm, and the land shoulders were rounded due to the O 2 plasma treatment. Figure 1 shows a DWDD film stack.…”

“…Domain wall displacement detection (DWDD) 1) is an excellent method for achieving high recording density on magneto-optical (MO) disks. Over the past few years, a considerable number of studies have been carried out on DWDD disks using a red laser diode (LD) [2][3][4] and a blue LD. 5,6) Tanaka et al reported two types of DWDD disks, an anneal-less type and a sidewall-annealed type, which enabled a land/groove recording of 15 Gbit/in 2 using a wavelength of 660 nm and a numerical aperture (NA) of 0.6.…”