Interface tribology for 100 Gb/in 2

Abstract

Critical head/disk interface requirements for 100 Gb/in 2 recording systems are examined with an emphasis on head design, head/disk protective overcoats and disk lubrication. A magnetic spacing of 10 nm that is necessary to achieve the areal density requires implementation of new technologies in each of these areas. To support the 100 Gb/in 2 areal density, novel air bearing surface (ABS) designs conceived to meet the low flying height requirement are presented. Numerical evaluation of various parameters necessary for optimum flying performance is discussed. These simulation studies provide guidance on the tolerance values and other aspects of the fabrication process that are needed to produce heads with low flying standard deviation. In an ultra-high density recording (100 Gb/in 2) system, the media property and the head–media separation distance become extremely important. To minimize the risk of head–disk interactions at low flying heights, super-smooth media with ultra-low glide heights will be needed. Reducing disk flutter at high rotational speeds will be a key issue affecting both the reliability of the interface and the electrical performance. Surface topography of such media will need to be on the order of atomic dimensions. Alternative substrate materials with higher stiffness and damping capacity are discussed as a solution to the above issues. The DLC coating on the air bearing and the transducer is another critical spacing parameter and alternate processing techniques of depositing ultra-thin carbon film are being explored. Lubricant thickness on the order of 1 nm will be applied to accommodate the decrease in the head–media spacing. Tribological measurements will be more crucial in ensuring a reliable head–disk interface for 100 Gb/in 2. These measurements are made even more difficult owing to the shrinking size of the sliders.