Interactions between nano-spacing flying head sliders and ultra-thin liquid lubricant films with non-uniform distribution in hard disk drives

Abstract

Interactions between nano-spacing flying head sliders and ultra-thin liquid lubricant films with non-uniform distribution in hard disk drives Abstract This paper describes the effect of ultra-thin liquid lubricant films on air bearing dynamics and flyability of less than 10 nm spacing flying head sliders in hard disk drives. In particular, the effect of non-uniform lubricant film distributions on head/disk interface dynamics are studied. The disks with lubricant on one half of disk surface thicker than the other half were used in this study. The dynamics of sliders is monitored using acoustic emission (AE) and the interactions between the slider and disk are investigated experimentally. The disks were also examined with a scanning micro-ellipsometer before and after each test. Complicated slider responses were observed and clarified. In addition, it was found that the periodic lubricant film thickness modulations or non-uniformity caused by the sliderdisk contact interactions could be observed. It is suggested that this lubricant film thickness non-uniformity will be one of the technical issues in order to achieve ultra-low head/disk contact interface of less than 10 nm.

Identification of the Spectrum Signature of Air-Bearing Slider Dynamics

“…To correlate the numerical simulations and experimental measurements, conventionally, a variety of linear models have been used to approximate system for parameter identification, which includes the conventional three-degree-of-freedom (3-DOF) model characterizing vertical translation, pitch, and roll angular motions of slider, 5-DOF, 6-DOF, and multiple-DOF models [7,11,[21][22][23][24][25][26][27][28]. On the other hand, there are many nonlinear models developed to characterize a variety of the nonlinear dynamic properties of interface together with 1-DOF, 2-DOF, 3-DOF, and 6-DOF [1][2][3][4][5][25][26][27][28]. To enable approximate analysis, simplified model has been derived from generalized Reynolds equation of air-bearing slider system:…”