Pole Tip Recession: Investigation of Factors Affecting Its Measurement and Its Variation With Contact Start-Stop and Constant Speed Drag Testing

Abstract

Optical interferometry and contact mode atomic force microscopy are used to investigate the various factors that influence the measurement of pole tip recession. These factors include: (a) effect of dissimilar materials on optical interferometry results, (b) size and location of the air bearing surface used as the reference area, (c) the effect of slider crown, (d) the magnification of the objective used in optical interferometry and (e) the dependence of the AFM measurements on slider materials and scan direction of the AFM tip. The possibility of determining a local value of pole tip recession is examined wherein the sputtered alumina, rather than the Al2 O3 -TiC surface, is used as the reference surface. Finally, the effect of contact start/stop (CSS) and constant speed drag testing on pole tip recession is investigated by measuring the change in pole tip recession as a function of the number of start/stop and constant speed drag cycles.