Towards 100 Gb/in2 MO storage using a blue laser, high-NA far-field optics and domain-exoansion media

A Magneto-Optical recording technology is described for storage densities of 50-100 Gb/in2 and data rates of 100-200 Mb/s. A sliding optical head which forms a key component for this recording technology has been developed. The head incorporates a thin-film coil for high data rate Magnetic Field Modulation recording and a dual lens objective with a Numerical Aperture of 0.85. To limit head-disc interface problems due to heating by the laser a cover layer of a few tens of μm is applied to the disc. Cover layer requirements are discussed and MFM recording results obtained with a NA=0.6 version of the sliding head and TbFeCo media with a thin cover layer are presented.