Slider and disk surface potential measurement by scanning Kelvin probe

Abstract

As the slider to disk surface spacing is reduced, the interfacial layers play an increasingly important role in determining performance characteristics. Surface potential measurements provide a valuable tool for exploring thin films and molecular layers on surfaces in general. Here we investigate surface potential measurement on magnetic recording slider and disk surfaces. The surface potential was measured over a range of carbon overcoat thickness to determine the depletion width. Increasing hydrogenation was found to decrease the surface potential. The excellent spatial resolution of the scanning Kelvin probe is illustrated by measurements on the rails of magnetic recording sliders. There is a significant effect of carbon overcoat and evaporated perfluoropolyether on the surface potential of the slider. Surface potential inside ultralow-flying-height test tracks prior to failure is less than that of the surrounding surface.