Corrosion behavior of Co-Sm based magnetic media

In this article the long term stability of Co-Sm thin films, both with no o vercoat and covered with silicon nitride layers of varying thickness, has b een investigated by means of accelerated corrosion tests in vacuum, air, an d in a humidity chamber. Bare Co-Sm films exhibit an accelerated decrease i n magnetization with respect to reference Co-Pt films, dependent in part on the effective surface area of the magnetic film. X-ray photoelectron spect roscopy depth profiling and corrosion tests demonstrate that silicon nitrid e layers of about 8 nm should provide adequate protection against degradati on of the magnetic properties of Co-Sm thin films. (C) 2001 American Vacuum Society.