Corrosion-resistant-rare-earth–transition-metal amorphous films with high recording sensitivity for magneto-optical disks

This study provides a method for improving the corrosion resistance of rare-earth–transition-metal films used for magneto-optical recording without depressing the recording sensitivity. This was attained by increasing Co content and substituting Dy for Tb and TbFeCo amorphous films. Potentiostatic polarization measurements indicate that the pitting potential of the film increases with the increase of Co content up to y=0.17 for (Tb0.5Dy0.5)0.21Fe0.79−yCoy. Attempts are made to explain the results using Auger electron spectroscopy and x-ray photoelectron spectroscopy. For the above-noted composition, both the Kerr rotation angle and coercivity observed through the substrate retain their initial values after the accelerated aging test. Results indicate that the (Tb0.5Dy0.5)0.21Fe0.62Co0.17 film offers superior characteristics for corrosion resistance without disturbing the magnetic properties.