We present the results of a XAS experiment carried out at the Ti 2p edge on well-ordered TiOx ultrathin films grown on the Pt(111) surface. XAS at the Ti 2p edge has been extensively applied to the study of Ti bulk compounds, particularly to the study of titania. According to the literature, the corresponding Ti 2p edge spectral shape is related to the stoichiometry and crystal field symmetry at the Ti sites. In the present study we aim at extending the potential of the XAS technique by discussing Ti 2p spectra obtained on several, dimensionally confined, TiOx phases in the form of ultrathin films. One of the main features of these films is their high degree of structural order. Furthermore, the results of previous studies provide valuable information about the chemistry and structure of the films, so that we are able to analyse the current XAS data in detail and to compare them with the appropriate Ti 2p XAS data of bulk oxides. We find that in the case of ultrathin film with a fully oxidised Ti4+ stoichiometry, the Ti 2p XAS data display features that are very similar to the ones observed in related bulk systems. The XAS data of the reduced TiOx films (with x<2) show a rather different and specific shape. By comparing the experimental spectra with an atomic type of model calculation we show that the Ti 2p XAS profiles can be attributed mainly to stoichiometry-symmetry effects.

Analysis of STM images of Fe grown on Cr and Cr grown on Fe with the exploitation of the differences of the Fe and the Cr surface state energies demonstrates strong intermixing during the epitaxial growth. We suggest a theoretical approach for modelling the epitaxial growth with subsequent self-consistent calculations of electronic and magnetic structure. On the basis of these calculations together with the experimental data obtained by complementary experimental methods, the structure of the interface on the atomic scale and the correlation between the chemical and magnetic roughness are investigated. We show that interface alloying is not symmetrical from both sides of the interface and suggest a scenario of the epitaxial growth that leads to this asymmetry.

The orientation of magnetic moments at the (100) surface of antiferromagnetic NiO single crystals is studied by x-ray linear magnetic dichroism in photoemission microscopy. T domains are observed terminating at the surface, with domain boundaries running mostly along in-plane [10] directions. From the detailed polarization dependence we find that the magnetic surface structure of a cleaved crystal is bulk terminated. This is in contrast to sputtered surfaces, where magnetic moments lie within the surface plane, forming a magnetically relaxed structure. These findings are of importance for understanding the exchange bias phenomenon.