High resolution electron energy loss spectroscopy study of Fomblin Z-tetraol thin films

Abstract

High resolution electron energy loss spectroscopy has been used to obtain vibrational spectra of Fomblin Z-tetraol lubricant films on a commercial magnetic hard disk. The energy loss intensities of the ͑CF 2 ͒ stretching mode are roughly independent of scattering angle up to angles of ⌬ Ͻ 14°indicating that they are excited by impact scattering. As a consequence there is little information that can be gleaned from the spectra about molecular orientation on the surface. A negative ion resonance enhances the energy loss cross section of the ͑CF 2 ͒ stretching mode at the impact energy of E I = 4 eV. It is possible that this resonance is associated with the known sensitivity of fluorocarbons to electron induced dissociation. Annealing the disk sample to T = 700 K causes a dramatic decrease in the intensity of C-F stretching modes and an increase of the loss features due to C-H stretching. This indicates that the Fomblin Z-tetraol has decomposed and is exposing the a-CH x overcoat on the magnetic media surface.