Microtribology of Magnetic Media

Abstract

Scanning tunnelling microscopy (STM), atomic force microscopy (AFM) and the modifications of AFM [such as friction force microscopy (FFM)] are becoming increasingly important in the understanding of fundamental mechanisms of friction, wear and lubrication and in studying the interfacial phenomena in micro- and nanostructures used in magnetic storage devices and microelectromechanical systems (MEMS). This paper describes modified AFM and FFM techniques and presents data on microtribological studies of magnetic media-magnetic tapes and disks. Local variation in microscale friction is found to correspond to the local slope, suggesting that a ratchet mechanism is responsible for this variation. Wear rates for magnetic tapes are approximately constant for various loads and test duration. However, for magnetic disks, the wear of the diamond-like carbon overcoat is catastrophic. Evolution of the wear has also been studied using AFM. AFM has been modified for nanoindentation hardness measurements. It has been shown that hardness of ultra-thin films can be measured using AFM. AFM has also been shown to be useful for nanofabrication.