ROLE OF DISK SURFACE-ROUGHNESS ON SLIDER FLYING HEIGHT AND AIR-BEARING FREQUENCY

The head-disk interface spacing must be decreased to increase the recording density in rigid disk drives. As the spacing decreases to sub submicron levels (<100 nm), the effect of the surface roughness on the dynamics of the slider needs to be understood. In this paper, we measure the flying heights and air-bearing frequencies during the transition from flying to sliding as a function of disk speed for thin film disks with various roughness magnitudes using the multi-channel laser interferometer and a laser-Doppler vibrometer. An acoustic emission transducer is also employed to detect head-disk contact. We observed no significant differences in the flying heights or air-bearing frequencies for different disk roughnesses at the tested speeds, but the landing speeds for the smoother disks were lower. It was found that the landing speed of a slider does not correlate with rms surface roughness, but is more a function of asperity peak heights. © 1990 IEEE