Magnetic force scanning tunneling microscopy of high density recording

Abstract

The magnetic force scanning tunneling microscope has been used to investigate the characteristics of magnetization patterns on rigid thin-film disk media, having wavelengths in the range from 20 to 1 μm. The images, which directly exhibit magnetic field distributions, compare favorably with a theoretical model that incorporates the ratio of the transition length relative to the bit length. The profiles of the long to intermediate wavelength patterns were analyzed to obtain estimates for the transition length parameter. At high recording densities, our results suggest two major contributing effects responsible for signal loss: (a) reduction in the magnetization and (b) ‘‘bit cluster formation.’’ As the wavelength is decreased, the tracks eventually lose the capability to retain the recorded pattern, and merely appear as a more or less random distribution of localized ‘‘magnetic patches’’ on the surface.