Electrostatically tunable adhesion in a high speed sliding interface

TL;DR

This study investigates electrostatic control of contact hysteresis in high-speed head-disk interfaces, revealing that AC voltage-induced oscillations can eliminate hysteresis despite electrostatic attraction.

Contribution

It demonstrates for the first time that AC electrostatic voltage can suppress contact hysteresis at high sliding speeds in commercial hard disk drives.

Findings

AC voltage induces out-of-plane oscillations of the head.

Oscillations suppress contact hysteresis.

Electrostatic force can be effectively controlled at high speeds.

Abstract

Contact hysteresis between sliding interfaces is a widely observed phenomenon from macro- to nano- scale sliding interfaces. Most of such studies are done using an atomic force microscope (AFM) where the sliding speed is a few {\mu}m/s. Here, we present a unique study on stiction between the head-disk interface of commercially available hard disk drives, wherein vertical clearance between the head and the disk is of the same order as in various AFM based fundamental studies, but with a sliding speed that is nearly six orders of magnitude higher. We demonstrate that although the electrostatic force (DC or AC voltage) is an attractive force, the AC voltage induced out-of-plane oscillation of the head with respect to disk is able to suppress completely the contact hysteresis.