Sputtered Tb/FeCoTi Multilayered Films for magneto-optical recording

The magnetic properties of Tb/FeCoTi multilayered films, prepared by two-source DC magnetron sputtering, have been investigated as a function of the layer thickness to improve the recording sensitivity of magnetooptical disks. For a fixed bilayer thickness ratio, the Curie temperature, T/sub c/, was strongly dependent on the Tb layer thickness and reached a maximum near 4 AA. The Kerr rotation theta /sub k/ is almost constant, independent of the Tb layer thickness. The effective composition shifts to the transition-metal-rich side with increase in Tb layer thickness, greater than 4 AA, made possible a pronounced reduction in T/sub c/ and effective composition adjustment, without decreasing theta /sub k/. Studies on recording characteristics revealed that recording sensitivity and bias magnetic fields are controlled by the Tb layer thickness, without sacrificing carrier-to-noise ratio. >