Surface texture parameters of perpendicular recording magnetic disks

This paper presents measured surface texture parameter values critical for evaluating the mechanical reliability of the head-disk interface in perpendicular magnetic recording with a small clearance of less than 1 nm. It was found that mean asperity height is ~0.5 nm and asperity density is ~5000 μm^-2. The asperity radius of curvature has an anisotropic nature but its averaged value is ~20 nm. The radius of highest asperity group related to asperity contact appears to be close to ~10 nm.