Smear Growth of Siloxane Outgas at Laser Heating

Siloxane outgas is well known to cause smears on magnetic head sliders. Siloxane outgas is vaporized from certain components in hard disk drives (HDDs), that adsorbs on the magnetic disk surfaces, and SiO2 that is denatured from siloxane by flash temperature at a slider and disk contact gets accumulated on the slider surface. On the other hand, heat assisted magnetic recording (HAMR) is being developed to improve areal density. In HAMR, a laser light heats the magnetic disk surface to 400–500 K. Siloxane adsorbed on a disk surface easily gets desorbed from the disk surface owing to thermal evaporation and dissociation by laser heating. In this study, we have studied smear growth from siloxane outgas on laser heating. We observe that the siloxane adsorbed on the disk surface grew on the glass surface above the disk surface at the laser heating spot.