Evaporated Co/Pt layered structures for magneto-optical recording

The authors discuss the properties of thin (<500 AA) Co/Pt layered structures (LSs) or multilayers for magnetooptical recording. These LSs have a perpendicular magnetic anisotropy, part of which is attributed to an interface anisotropy contribution. LSs with Co layer thicknesses of 4 AA or less than Pt layer thicknesses of 10-20 AA thick have a 100% magnetic remanence and a Kerr rotation, theta /sub k/, of -0.1 degrees to -0.2 degrees as well as optical reflectivity R=70%, both at lambda =820 nm. The Curie temperature of these LSs is between 300 and 400 degrees C. The authors also present the first disk performance data for Co/Pt LSs. A pregrooved disk was coated with AlN and a 23*(3.5 AA Co+13 AA Pt) LS, and, although the figure of merit R theta /sup 2//sub k/ was not fully optimized, a carrier/noise ratio of 49 dB was achieved. This, together with the excellent magnetic properties and high oxidation resistance, makes these Co/Pt LSs very promising candidates for magnetooptical recording. Furthermore, theta /sub k/ increases at shorter wavelengths where still higher recording densities are possible.<
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