Flying stiction, lubricant pick-up and carbon-overcoat wear of magnetic heads

Flying stiction, a high static friction force resulting from a magnetic hea d seeking/flying over a disk surface, has posed a new challenge in magnetic -disk tribology for low flying heights (similar to 30 nm or less), as deman ded by high recording densities. Two types of magnetic heads were used in t his study. A more than 10-fold increase in flying stiction force was observ ed for the carbon coated heads after a 24 hours of seeking/flying over the disk surface. Using Time of Fright Secondary Ion Mass Spectroscopy and a sc anning micro-ellipsometer we found that the lubricant pick-up during seekin g/flying operation was responsible for the observed 10-fold increase of the flying stiction force. A nearly exponential dependence of flying stiction force on lubricant amount picked lip on the air bearing surface (ABS) of th e magnetic heads was Sound. For 24 hours of seeking/flying time, the lubric ant accumulated on the ABS surfaces can be up to 1.5 nm, comparable to the lubricant thickness on the disk surfaces. The lubricant amount was Sound qu ite uniformly distributed over the ABS surface of the head Wear on the carb on overcoat of the magnetic heads was also measured, and was equivalent to approximately 1 nm carbon loss for a 24-hour seeking/flying period. The wea r rate of the carbon overcoat was very fast for short periods of seeking ti me (similar to 2 hours) and slowed down to near-zero as lubricant built up on the ABS surface, indicating that the lubricant on the head protected car bon wear: The wear of carbon overcoat strongly suggests that intermittent p hysical contacts between the disk surface and head ABS occurred during seek ing/flying operations.