Double compensation point media for direct overwrite

Two magneto-optic media configurations are discussed that are suitable for direct overwrite by light intensity modulation using only one conventional bias magnet. One configuration consists of two magnetic layers (memory and reference having perpendicular anisotropy) exchange coupled through an intermediate soft magnetic layer. The second media configuration consists of only a memory layer and an intermediate layer. This scheme produced a respectable direct overwrite performance of 48 dB using a 3.5 μm mark size, 30 kHz bandwidth, and 7 m/s disk velocity. The major advantages of this scheme are simpler disk structures relative to a previously proposed quadrilayer scheme, and a wide range for Curie temperatures, thicknesses, and coercivities of the individual layers.