Data Storage Systems Center

In hard disc drives (HDD), it is imperative to reduce total head media spacing (HMS) in order to achieve higher recording density. However, HMS of the current state of the art HDD, physical fly height (PFH) is almost the lowest limit due to the adoption of thermal fly height control, and therefore the major portion is occupied by carbon overcoat for physical/chemical surface protection and lubricant thcknesses, meaning that a very small room is left for further HMS reduction. A researcher in the DSSC proposed a new concept for realizing continuous contact head media interface (HMI) utilizing surface acoustic wave. This concept, name as surface acoustic wave – active bearing (SAW-AB) project, in principle requires no lubricant layer yet can achieve zero friction/wear while maintaining continuous mechanical contact. Some basic theoretical calculations suggest that the linear speed of a few tens of m/s may be achievable, which is comparable with the current HMI linear velocity, without requiring large power injection. In order to prove this concept, a feasibility study has already begun. One experiment showed that the attractive surface interaction due to Van der Waals force for insulators and metal-to-metal bonding for conductors can be diminished by SAW excitation. Another experiment showed that SAW excitation actually generates lateral traction force even when the SAW frequency is as high as about 300MHz. These promising results are presented in the poster in more details.