Absence of oxide formation at the Fe/MgO(001) interface

We present a study focussed at the atomic level characterization of the Fe/MgO(0 0 1) interface by means of X-ray photoelectron spectroscopy, X-ray photoelectron diffraction and X-ray absorption spectroscopy. The data show a good crystalline quality of the Fe films grown on MgO(0 0 1) at room temperature. The films have a bcc structure with the Fe(0 0 1)//MgO(0 0 1) and Fe[1 1 0]//MgO[1 0 0] orientation. The Fe growth in the 1-10 ML thickness range proceeds by the formation of islands covering a fraction of the MgO surface. The oxidation of Fe and the consequent reduction of MgO can be excluded, thus proving that the interface is locally abrupt, with a very weak interaction between the two sides. The interface is stable with temperature up to 670 K.