Multiscale Modeling of Head Disk Interface

Multiscale modeling opens a new paradigm by providing a novel methodology of establishing molecular design criteria and potentially gives several order of magnitude advances in nano-technology. The head disk interface in hard disk drive system investigated here can be used as a benchmark for multiscale modeling. Our approach, stemmed from novel middle-out approach in modern multiscale modeling, uses lattice Boltzmann method (LBM) as a base formulation marches towards continuum level (top) and molecular level (bottom). This approach will be an extremely valuable tool in generating design criteria of head/disk interface.

I. Introduction

Hard disk drives (HDDs) have been one of the most dominant information storage devices. With continuous increase in areal density, the head media spacing (HMS), containing head overcoat, media overcoat, perfluoropolyether (PFPE) lubricant film, and fly height, is expected to reduce to 6.5 nm for 1 HDDs so that an accurate description and nanoscopic control of the head disk interface (HDI) becomes critical for the HDD performance and reliability [1]. With such stringent space requirements within the HMS, demand for novel techniques to investigate the HDI dynamics increases. Multiscale modeling has recently opened a new paradigm by providing a novel methodology of molecular design criteria and potentially gives several order of magnitude advances in nano-technology. The HDI can be an excellent benchmark for multiscale modeling since the system includes molecular scale thin lubricant film adjacent to the rarified gas flow region between the head and the disk, which can be examined by nano/meso/macro-scopic modeling. In addition, alternative technology like heat assisted magnetic recording (HAMR), requires nano/micro scale heat transfer modeling.