Nanotribological and nanomechanical properties of lubricated PZT thin films for ferroelectric data storage applications

Lead zirconate titanate (PZT) is a desirable material for nonvolatile data storage due to its ferroelectric properties. Evaluating the nanoscale mechanical and tribological performance of PZT is crucial in understanding the reliability of this material. To this end, the mechanical properties of the PZT film were characterized by nanoindentation. Nanoscratch studies reveal that the PZT film is removed by a combination of plastic deformation and brittle failure. The adhesion, friction, and wear properties of PZT were evaluated before and after application of two lubricants, namely, the perfluoropolyether Z-TETRAOL and the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate $(BMIM-PF6)$⁠. Wear at ultralow loads was simulated and the lubricant removal mechanism was investigated for the first time using atomic-force-microscopy-based surface potential and contact resistance techniques. From this study, ionic liquids were found to exhibit comparable nanotribological properties with Z-TETRAOL.