Ultrathin Si/C graded layer to improve tribological properties of Co magnetic films

An ultrathin Si layer (<= 1 nm) deposited on Co magnetic films was bombarded with energetic C+ ions to form a Co/Si/C mixed layer. This layer improved the tribological properties of the Co film as compared with those of a commercial hard disk media with 3.0 nm carbon overcoat and 1.4 nm of lubricant. Formation of a network of C-C and Si-C bonds at the outermost layer and the bulk of the Si/C film as well as formation of chemical bonds between the Co surface and the mixed layer was found as the main factors to improve the tribological properties. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4765054]