Acoustic emission and stiction analysis of patterned laser textured media

The take off behavior of pico and nano sliders is investigated in the time and frequency domain using acoustic emission analysis. Laser textured disks with high and low bump densities and with various bump heights were fabricated. W-shaped and V-shaped laser bumps were produced in "row" and "column" like patterns. For these matrix arranged bump patterns, the bump pattern frequency, corresponding to the bump spacing, was found in the spectrum of the AE signal. A smoother and faster slider take-off was observed to occur if the circumferential spacing between laser bumps was reduced relative to the radial spacing. Also, a reduced bump height was found to decrease the take-off time. The stiction force during startup was found to be reduced for low density bump patterns. Torsional and bending mode excitations of the slider-body were observed to occur primarily with high density patterns. The rms acoustic emission signal was found to be generally lower for low density bump patterns than for high density patterns.