Anisotropic scaling of hard disk surface structures

We present a detailed study of the surface roughness of a computer hard dis k using atomic force microscopy and light scattering. The power spectrum de nsity analysis showed that the surface possesses an anisotropic scaling beh avior and has both random roughness and periodic roughness components. Quan titative anisotropic correlation length (xi) and roughness exponent (alpha) for the directions parallel and perpendicular to the grooves are obtained. A novel in-plane (measurement parallel to the sample surface) light scatte ring technique is shown to be particularly useful for the analysis of the r ough surface parallel to the grooves. (C) 2000 American Institute of Physic s. [S0021-8979(00)04019-6].