Time-Frequency Analysis of Slider Dynamics and the Effect of Lubricant

The dynamics of pico sliders is investigated during scratch impact using laser Doppler vibrometry. Air-bearing frequencies and damping of the pitch-2 frequency are studied as a function of disk velocity for lubricant thickness values of 1.6 nm, 1.0 nm and 2.0 nm. Time-frequency analysis is performed to study the instantaneous air-bearing frequencies. System identification methods are used to model the response of the slider after a scratch impact. The results indicate that the slider dynamics and the damping coefficients are affected by the disk velocity and lubricant thickness and also possibly by disk micro-waviness.