NUMERICAL AND EXPERIMENTAL INVESTIGATION OF NANOSCALE HEAT TRANSFER IN THE HEAD-MEDIA INTERFACE DURING STATIC TOUCHDOWN

With minimum fly height of less than 10 nm in contemporary hard-disk drives, understanding nanoscale heat transfer at the head-media interface is crucial for developing reliable head and media designs. Particularly, with the emergence of HeatAssisted Magnetic Recording (HAMR) and Microwave-Assisted Magnetic Recording (MAMR), head failure due to overheating has become an increasing concern. There is a need to develop a methodology to use theoretical curves for spacing -dependent nanoscale heat transfer coefficient to predict head and media temperatures in actual hard disk drives. In this study, we present a numerical model to simulate the head and media temperature profiles during static touchdown and compare our results with experiments performed with a magnetic head on a silicon wafer. As the head approaches touchdown with increasing TFC power, the phonon conduction heat transfer coefficient between the head and the substrate increases exponentially, causing a drop in the head temperature vs TFC power curve. Our model shows that the introduction of van der Waals forces between the head and the substrate causes a steeper drop in the head temperature curve and ensures a good quantitative match with experimental results.