MAGNETIC FORCE SCANNING-TUNNELING-MICROSCOPY OF HIGH-DENSITY RECORDING

The magnetic force scanning tunneling microscope has been used to inve stigate the characteristics of magnetization patterns on rigid thin-fi lm disk media, having wavelengths in the range from 20 to 1 mum. The i mages, which directly exhibit magnetic field distributions, compare fa vorably with a theoretical model that incorporates the ratio of the tr ansition length relative to the bit length. The profiles of the long t o intermediate wavelength patterns were analyzed to obtain estimates f or the transition length parameter. At high recording densities, our r esults suggest two major contributing effects responsible for signal l oss: (a) reduction in the magnetization and (b) ''bit cluster formatio n.'' As the wavelength is decreased, the tracks eventually lose the ca pability to retain the recorded pattern, and merely appear as a more o r less random distribution of localized ''magnetic patches'' on the su rface.