Title :
Write-induced pole-tip-protrusion and its effect on head-disk interface clearance
Author_Institution :
Western Digital Corp., San Jose, CA, USA
fDate :
7/1/2004 12:00:00 AM
Abstract :
Write-induced pole-tip-protrusion (WPTP) and its effect on head-disk interface (HDI) clearance are studied. Drives are placed in a vacuum chamber and the contact altitude is used in this study together with triple harmonic method. It is found that write-induced PTP is a function of the write-signal frequency and the write duration of the head. The magnitude of the WPTP is on the order of nanometers. For a state-of-the-art HDI design with nominal flying height around 10 nm, WPTP can reduce the HDI clearance dramatically. It can cause write modulation and altitude failure. In order to improve the HDI reliability, WPTP must be taken into account.
Keywords :
harmonic analysis; magnetic heads; magnetic recording; HDI clearance; HDI reliability; altitude failure; altitude sensitivity; contact altitude; head write duration; head-disk interface clearance; nominal flying height; state-of-the-art HDI design; triple harmonic method; vacuum chamber; write modulation; write-induced pole-tip-protrusion; write-signal frequency; Coils; Eddy currents; Frequency; Hard disks; Heating; Helium; Magnetic heads; Magnetic hysteresis; Optical losses; Testing; Altitude sensitivity; head-disk interface clearance; pole-tip-protrusion; triple harmonic method;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2004.830224
