Study on the Adsorption and Thermal Diffusion of D-4OH Lubricant on Amorphous Carbon Film by Reactive MD Simulation for HAMR

Abstract

Heat-assisted magnetic recording (HAMR) is an innovative type of storage technology. The PFPE lubricants can improve the friction properties of the HAMR head-disk interface (HDI) in the writing and reading processes. The adsorption and thermal diffusion processes of three D-4OH lubricants with polar functional end groups on amorphous carbon (a-C) film are investigated by reactive molecular dynamics simulation. The potential energy, atomic distribution, radial distribution function (RDF), bonds’ number, atomic migration vector, and atomic shear strain are analyzed both in the relaxation and heating processes. The H atoms of polar functional end groups of D-4OH are bonded with a-C unsaturated carbon atoms via the secondary bonds. The main chains of D-4OH lubricants are adsorbed by a-C film via van der Waals forces. Laser heating helps to enhance the adsorption performance of lubricant on an a-C surface at a low temperature. The thermal diffusion of the lubricant makes the lubricant form a more stable conformation on the surface of the a-C film. Increasing the amount of −OH can improve the adsorption of PFPE lubricant on the a-C film.