NUMERICAL AND EXPERIMENTAL INVESTIGATION OF NANOSCALE HEAT TRANSFER BETWEEN A FLYING HEAD OVER A ROTATING DISK

With the minimum fly height less than 10 nm in contemporary hard-disk drives, understanding nanoscale heat transfer at the head-disk interface (HDI) is crucial for developing reliable head and media designs. While flying at near-contact, the fly height and spacing dependent nanoscale heat transfer are significantly affected by interfacial forces in the HDI (such as adhesion force, contact force etc.). Moreover, with the emergence of technologies such as Heat-Assisted Magnetic Recording and Microwave-Assisted Magnetic Recording, head failure due to overheating has become an increasing concern. In this study, we present a numerical model to simulate the head temperature profile and the head-disk spacing for a flying head over a spinning disk and compare our results with touchdown experiments performed with a magnetic recording head flying over a rotating Al-Mg disk. In order to accurately predict the fly height and heat transfer at near-contact, we incorporate asperity based adhesion and contact models, air & phonon conduction heat transfer, friction heating and the effect of disk temperature rise in our model. Our results show that the incorporation of adhesion force between the head and the disk causes a reduction in the fly height, leading to a smaller touchdown power than the simulation without adhesion force.