Microtribodynamics of pseudo-contacting head-disk interfaces intended for 1 Tbit/in2

As the distance between the magnetic recording slider and the high-speed rotating disk decreases to few nanometers, it is critical to understand the tribological and dynamic interaction at the head-disk interface (HDI). Such interaction involves surface topography, adhesion, friction, and system dynamic coupling and is termed microtribodynamics. A two degree-of-freedom nonlinear dynamic model that includes realistic roughness, adhesion, and friction, as well as the dynamics of a flying and contacting HDI was developed to characterize a pseudo-contacting HDI, intended for 1 Tbit/in². While a fully flying HDI is intended to avoid contact, a pseudo-contact recording system is designed to fly at few nanometers using an air-bearing and at the same time some features of the air-bearing surface are designed to contact with the rotating disk during operation. The model was favorably compared with flyability measurements, and then applied to a pseudo-contacting interface to investigate adhesion, friction, and contact forces as well as bouncing vibration. Contrasting earlier studies adopting a simple Coulomb friction, the friction model used in this work calculates the friction force at the interface, accounting for roughness and adhesion. It was found that unlike a fully flying HDI, adhesion plays a positive role in attaining pseudo-contact recording by reducing bouncing vibrations.