Magneto-optical recording on evaporated Co/Pt multilayer films

Co/Pt multilayers composed of 0.3-nm Co and 1-nm Pt layers were prepared by e-beam evaporation from Co and Pt sources. These Co/Pt multilayers with a total film thickness of 20-30 nm have a large perpendicular magnetic anisotropy, a perpendicular hysteresis loop with a saturated remanence, a coercivity of about 1.8 kOe, and a Curie temperature of about 300°C. They are structurally stable enough for thermomagnetic magnetooptical recording. Moreover, these Co/Pt multilayers are corrosion resistant and have enhanced Kerr rotation at short wavelengths. On a disk of 15×[Co(0.32 nm)/Pt(1.15 nm)] multilayer enhanced with 80-nm silicon nitride, a CNR (carrier-to-noise ratio) of 59 dB was achieved with a reading laser (λ=820 nm) power of 1 mW for a 2-MHz carrier at 10 m/s, and 64 dB with 3-mW read power for a 2.5-MHz carrier at 20 m/s. It is concluded that these Co/Pt multilayers are very promising as magnetooptical recording materials