Experimental study of slider dynamics induced by contacts with disk asperities

Vertical vibrations at the slider leading edge exited by a disk asperity were investigated in a drive level system, using laser Doppler vibrometry and acoustic emission (AE) sensors. The flying height change at the leading edge of a thermal flying-height control slider was measured for different power inputs to the heater element. The maximum spacing change at the slider leading edge was found to be about 4 nm for an asperity of 26 nm height and 1.1 μm width. A method was investigated to produce "artificial asperities" on a disk surface using a nano-indentor. The geometry of the "artificial asperities" was characterized using an atomic force microscope. In addition, a spin stand was used to analyze the AE signal of slider vibrations induced by contacts with the "artificial asperities". First and second pitch modes of the slider were observed.