Fe-Co-B/Ni-Fe Thin Film with a High Magnetic Anisotropy Field for the Soft Magnetic Underlayer of Perpendicular Magnetic Recording Media

摘要

A Fe-Co-B layer with a high 4πMs of 23 kG was investigated for a low-noise-type soft magneticunderlayer of perpendicular magnetic recording media. A Ni-Fe seedlayer was effective in attaininga high H_kand a low H_c for the Fe-Co-B layers. The origin of highH_kin B/Ni-Fe layerswas magnetoelastic anisotropy due to residual stress. The high Hi, exhibited a relatively strongdurability in the annealing process. Furthermore, the Fe-Co-B/Ni-Fe double layer with a high H_kexhibited a single domain pattern suited for a low-noise soft magnetic underlayer.