Pole tip recession studies of-film rigid disk head sliders II. effects of air bearing surface and pole tip region designs and carbon coating

摘要

Pole tip recession (PTR) results in an increase in spacing between recording elements and magneticmedia which is undesirable for highdensity recording. The effects of air bearing surface (ABS)designs, pole tip region designs and carbon coating on the growth of PTR with increasing start-stopcycles have been investigated. A better ABS design for less PTR should reduce contact time betweenslider and disk during take-off and landing of the slider. Among the two-rail, tail-dragger and negativepressure sliders, the negative pressure slider has shortest contact time during take-off and landing,followed by the two-rail slider and tail-dragger slider. The growth mechanisms of PTR for two-railslider with or without U-shaped slot consists of knocking-off protruded poles, generation of wearparticles and three-body abrasive wear. The PTR reaches a saturated value after a certain start-stopcycles. However, for the tail-dragger slider with square-shaped slot, there is a fourth step of erosionwhich leads to no saturation of PTR and a relatively rough surface of poles. Mechanisms of PTR fornegative pressure slider is similar to the two-rail slider but with a lower saturated PTR value. Carboncoating minimizes or eliminates the PTR growth through reducing static and kinetic friction duringtake-off and landing, providing a wear-resistant protective layer and eliminating dissimilarities of ABS,thin film structure and poles. Based on this study, we find that negative pressure slider whichminimizes contact at head-disk interface and carbon coating which protects thin-film region aredesirable alternatives for slider designs. Initial recession is desirable as compared to protrusion.