Magnetic thin film media with a protective layer of CNx having a plurality of compositions

摘要

A thin film structure comprising a protective layer structure having at least two different compositions of carbon and nitrogen with the surface of the protective layer having the lowest nitrogen content is disclosed. The protective layer structure of the invention is preferably used over the magnetic material in a thin film magnetic disk. In the protective layer structure of the invention, the durability of a relatively high nitrogen content CNx material is improved by the addition of a surface sublayer of CNx with a relatively low nitrogen concentration. The resulting protective layer structure provides superior durability to either of the thin film compositions used alone achieving a synergistic result. The protective layer structure of the invention has the additional benefit of decreasing the polar surface energy and therefore, improving the corrosion resistance of the film structure. In one embodiment the protective layer of the invention is implemented as two discrete sublayers with the surface sublayer having the lowest nitrogen concentration. In this embodiment the surface sublayer has from 0 to 8 at. % nitrogen and the higher nitrogen content is between 10 and 25 at. % nitrogen at the magnetic layer interface. The protective layer structure of the invention can also be implemented as a film in which the nitrogen content gradually decreases between the magnetic layer and the surface of the protective layer structure.