Published online by Cambridge University Press: 14 January 2011
Both low and high resistance states (which were written by voltage application in a local region of NiO/Pt films using conducting atomic force microscopy [C-AFM]) were observed with scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). The writing regions are distinguishable as dark areas in a secondary electron image and thus can be specified without using a complicated sample fabrication process to narrow down the writing regions such as the photolithography technique. In addition, the writing regions were analyzed using energy-dispersive x-ray spectroscopy (EDS) mapping. No difference between the inside and outside of the writing regions is observed for all the mapped elements including C and Rh. Here, C and Rh are the most probable candidates for contamination that affect the secondary electron image. Therefore, our results suggested that the observed change in the contrast of the secondary electron image is related to the intrinsic change in the electronic state of the NiO film and a secondary electron yield is correlated to the physical properties of the film.