Spinstand Measurement of Head Keeper Spacing in Perpendicular Recording

Abstract

We have developed a method to measure HKS from the playback waveform from a specific recording pattern.In the current high-density perpendicular magnetic recording system, the head air-bearing surface (ABS) to soft under-layer (SUL) surface, or so called head keeper spacing (HKS) is one of the key parameters that affect both writer field strength as well as playback process. Here we describe the principle and procedure we used to infer HKS from measurement. The result on HKS using 1st and.3rd signal harmonics is discussed and rechecked with that using 1st and 5th harmonics. The effect of head surface potential change due to the HKS variation. As the head media spacing (HMS) and thus HKS is reduced with increased areal density, its impact on system performance will be more significant. Thus, the measurement of HKS is important.