Abstract
To increase the recording density of magnetic disk, the flying height of magnetic head slider from the substrate surface has recently been strongly requested to be minimized. This report aims to investigate the influence of the substrate smoothness on the flying height. The smoothness is examined from the standpoint of the slight undulation, Hw, and the surface roughness, Hs, which are the surface topography of 50 μm length measured with Talystep and of 4 mm length measured with WYKO, respectively. First of all, the substrates of the smoothness, Fs (= Hw+Hs), of about 1 nm to 35 nm (P-V value) are prepared by polishing with Al2O3 and SiO2 abrasives after clearing the slight undulation and the surface roughness formed by polishing. Next the relationship between the minimum flying height and the smoothness is discussed by examining the minimum flying height of magnetic head slider from the substrate surface. The minimum flying height decreases in proportion with decreasing the Fs. In the experiment, the minimum flying height could be decreased up to about 10 nm. The flying height increases in case of texturing the ultra smooth substrate because of the smoothness deterioration.
