Structural and compositional stability of Co oxide grown on (001) bct Co

Room temperature (RT) adsorption of oxygen on the (001) surface of metastable, cubic Co film epitaxially grown on a Fe substrate results in the formation of about 7 monolayers (ML) crystalline CoO film, in the typical rocksalt structure 45 degrees rotated with respect to the square unit mesh of the underlying Co film. We investigated the stability of this oxide layer upon annealing in the RT-620 K temperature range, by means of primary-beam diffraction modulated electron emission (PDMEE), and X-ray photoelectron spectroscopy (XPS). For temperatures up to 570 K, film thickness and local order are preserved, in spite of an increasing number of Co and O atoms bonded in sites of reduced coordination For larger temperatures, thickness also reduces, but the oxide film is still characterized by a high degree of CoO-like local order. (C) 1999 Elsevier Science B.V. All rights reserved.