POLE TIP RECESSION STUDIES OF THIN-FILM RIGID DISK HEAD SLIDERS - II - EFFECTS OF AIR-BEARING SURFACE AND POLE TIP REGION DESIGNS AND CARBON COATING

Pole tip recession (PTR) results in an increase in spacing between rec ording elements and magnetic media which is undesirable for high-densi ty recording. The effects of air bearing surface (ABS) designs, pole t ip region designs and carbon coating on the growth of PTR with increas ing start-stop cycles have been investigated. A better ABS design for less PTR should reduce contact time between slider and disk during tak e-off and landing of the slider. Among the two-rail, tail-dragger and negative pressure sliders, the negative pressure slider has shortest c ontact time during take-off and landing, followed by the two-rail slid er and tail-dragger slider. The growth mechanisms of PTR for two-rail slider with or without U-shaped slot consists of knocking-off protrude d poles, generation of wear particles and three-body abrasive wear. Th e PTR reaches a saturated value after a certain start-stop cycles. How ever, for the tail-dragger slider with square-shaped slot, there is a fourth step of erosion which leads to no saturation of PTR and a relat ively rough surface of poles. Mechanisms of PTR for negative pressure slider is similar to the two-rail slider but with a lower saturated PT R value. Carbon coating minimizes or eliminates the PTR growth through reducing static and kinetic friction during take-off and landing, pro viding a wear-resistant protective layer and eliminating dissimilariti es of ABS, thin film structure and poles. Based on this study, we find that negative pressure slider which minimizes contact at head-disk in terface and carbon coating which protects thin-film region are desirab le alternatives for slider designs. Initial recession is desirable as compared to protrusion. (C) 1998 Elsevier Science S.A. All rights rese rved.