Epitaxial growth of CoO on the (001) surface of bct cobalt

Adsorption of oxygen on a (001) surface of 10 monolayers thick, metastable cubic Co film epitaxially grown on the Fe(001) surface was studied at 300 and 470 K by means of primary-beam diffraction modulated electron emission, X-ray photoelectron spectroscopy and Auger electron spectroscopy. At 300 K, the formation of CoO in the very first layer was observed, in the typical rock salt structure, 45 degrees rotated with respect to the square unit mesh of the remaining, underlying Co film. At 470 K, the oxide extends in thickness involving the whole Co film. Similar behavior has been observed for the (11 (2) over bar 0) surface of the hcp phase. On both surfaces, the oxide layer appears tetragonally distorted. (C) 1998 Elsevier Science B.V. All rights reserved.