181. EXPERIMENTAL AND NUMERICAL INVESTIGATION OF SLIDER DISK CONTACT IN HARD DISK DRIVES
Name: Liane Manuela Matthes
Grad Year: 2015
Numerical and Experimental Investigation of Slider-Disk Contact in Hard Disk Drives Hard disk drives (HDD) have remained the dominant device for secondary data storage due to their low cost per data unit. Since their introduction by IBM in the early 1960s, the storage capacity has increased from 5 MB to 3 TB in 2011. In hard drives, data are stored in data tracks along the circumference of a rotating, magnetic disk. The read and write elements are embedded in the so-called slider that flies over the disk supported by an air bearing. To achieve higher storage densities, the distance between the slider and the disk needs to be reduced in order to maintain a sufficient signal-to-noise ratio which is required for proper reading and writing. The head-disks spacing of today's HDDs is on the order of 2-3 nm which is less than one ten thousands of the diameter of a human hair. At such a low spacing, intermittent contact between slider and disk becomes inevitable due to imperfections of the disk and vibrations during disk operation. However, contacts between slider and disk are undesirable, since it could cause erasure of magnetically stored information, wear, lubricant transfer or even failure of the hard drive. Thus, intermittent contact between slider and disk is becoming a major concern of the HDD industry as the head-disk spacing is reaching the sub-nanometer level. In this study, numerical and experimental methods including molecular dynamics simulations are used to investigate phenomena occurring during slider-disk contact. Finite element simulations are employed to investigate the contact between the slider and asperities on the disk. The theory of molecular dynamics is employed to model the lubricant behavior during slider-disk contact. Furthermore, experiments are performed on a spin stand to investigate slider /disk vibrations and the resistance change of the read element is measured during slider-disk contact of thermal flying height control sliders.