Magneto-Optical Recording on Evaporated Co/Pt Multilaver Films

Abstract

Co/Pt multilayers comprising of about 0.3 nm Co and I 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 magneto-optical recording. Moreover, these Co/Pt multilayers are corrosion resistant, and have enhanced Kerr rotation at short wavelengths. On a disk of 15 x [Co(.32 nm)/Pt(1.15 nm)] multilayer enhanced with 80 nm silicon nitride, we have achieved a CNR of 59 dB with a reading laser (λ = 820nm) power of 1mW for 2 Mllz carrier at 10 m/s, and 64 dB with 3 mW read power for 2.5 MHz carrier at 20 m/s. These Co/Pt multilayers clearly are very promising as magneto-optical recording materials. © 1990 IEEE