The Spin-Off of Particles on a Magnetic Disk

Abstract

A spin-off ratio is used in this study to assess the repelling capability of a disk surface to thermal asperity for MR drives. A test methodology is described and a simple model is developed. Three types of spherical particles with different size and material properties are used in this study to evaluate the spin-off ratios of disks from various manufacturers and with different lubricant thickness and texture roughness. It is found that the dominant factors determining whether a particle is spun off a disk surface are the stiction force and the centrifugal force. Particle size and material properties, disk spinning speed, disk radius, surface tension and contact angle have significant effects on the spin-off ratio, while lubricant thickness and disk surface roughness have little effect. The manufacturing process and material used to produce a disk also affect how well the disk behaves when thermal asperity is a concern. [S0742-4787(00)03901-1]