Density Dependence of Carbon/Magnetic Layer for Corrosion/Scratch Resistance on Head-Disk-Interface

Each relative density of carbon overcoat and upper magnetic layer of perpendicular magnetic disks with different corrosion and scratch resistance was measured by transmission electron microscopy electron energy loss spectroscopy (TEM EELS). Corrosion resistance depends on the relative density of both layers, the carbon overcoat and the upper magnetic layer with higher density showed larger corrosion resistance. Scratch resistance did not depend on the density of carbon overcoat, but depended on the density of the upper magnetic layer. Higher density showed higher scratch resistance. This relationship between the relative density of upper magnetic layer and the scratch resistance suggests the deformation of upper magnetic layer affects to scratch damage. As the result of this study, the density evaluation by TEM EELS is useful to estimate the corrosion/scratch resistance tendency of perpendicular magnetic disks, and the higher density of upper magnetic layer is needed to improve the scratch robustness of perpendicular magnetic disks.