Comparative study of head-disk spacing measurement techniques between optical method and various in-situ methods

Abstract

The interaction between slider, lubricant and disk surface is becoming the most crucial robustness concern of advanced data storage systems. This paper reports comparative studies among various techniques for the measurement of head-disk spacing. It is noticed that the triple harmonic method gives a reading much closer to the reading of the head-disk spacing obtained optically at on-track center case, comparing with the PW50 method. Specially prepared disks with different carbon overcoat thickness (6.5nm, 11mn, 16nm and 22nm) were also used to study the reliability and repeatability of the triple harmonic method.