Visualisation of size-dependent particle deposition in a slider/disk interface

Abstract

As contamination will play a significant role in slider-based magneto-optical (MO) data storage systems, a novel experimental technique is proposed to enhance contamination visualisation. This technique is based on using mixtures of different sizes of monodisperse, fluorescent, spherical, polystyrene-latex particles, each size having a different fluorescent colour. Apart from the relatively easy visualisation of size-dependent particle deposition, validation of numerical simulations of particle deposition is also enhanced. The experimental results obtained with the fluorescent particles, which are soft, are compared with results obtained when harder, spherical, silicate particles are used. It is demonstrated that these hard particles are simply embedded in the polycarbonate disk, and cause no significant damage to, or contamination of, the slider. The soft fluorescent particles are not embedded, but smears and scratches on the disk surface are observed. The slider contamination is much more severe with the soft particles than with the hard silica particles, however, also when a hard glass disk is used. This indicates that the MO slider cannot simply be protected from contamination with soft particles by increasing the hardness of the disk. As many soft particles are present in the atmosphere, additional slider features will be needed to reduce slider contamination, and thereby the risk of system malfunction. Future numerical support of the development of such features is believed to be enhanced with the described experimental validation method.