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Monolithically integrating BaTiO3 on silicon substrates has attracted attention because of the wide spectrum of potential novel applications ranging from electronics to photonics. For optimal device performance, it is important to control the BaTiO3 domain orientation during thin film preparation. Here, we use molecular beam epitaxy to prepare crystalline BaTiO3 on Si(001) substrates using a SrTiO3 buffer layer. A systematic investigation is performed to understand how to control the BaTiO3 domain orientation through the thickness engineering of the SrTiO3 buffer layer and the BaTiO3 layer itself. This provides different possibilities for obtaining a given BaTiO3 orientation as desired for a specific device application.

Hard x-ray photoelectron spectroscopy (HAXPES), angle-resolved x-ray photoelectron spectroscopy (ARXPS) and x-ray photoelectron spectroscopy (XPS) with simultaneous Ar+ bombardment are used to obtain chemical information and concentration depth profiles of thin film oxides on Cr, Al, Si substrata and to explore the capabilities of analyzing buried interfaces at depths above 10 nm in Cr-O-Al thin films mixed oxides deposited on Si substrata. ARXPS and HAXPES are non-destructive techniques and within the photon energy range (7.5-15 keV) and the emission angle range (0°-70°) used, both techniques provide equivalent information, ARXPS being more sensitive to the surface morphology. XPS and simultaneous sputtering with Ar+ is a destructive technique and effects such as atomic mixing are unavoidable; however, the comparative study with HAXPES allowed the measurement of key parameters for the understanding of the ion-matter interaction such as the mixing extent and the interface broadening. © 2013 IOP Publishing Ltd., The financial support by the Ministerio de Ciencia e Innovación (MICINN) of Spain through the Consolider-Ingenio 2010 programme (CSD2008-00023) and through the project MAT2008-06618-C02 is gratefully acknowledged. CP thanks the Spanish Ministerio de Educación for financial support within the Programa Nacional de Movilidad de Recursos Humanos de Investigación (PR2011-0231). REG would also like to thank the MICINN for the financial support within the Ramón y Cajal programme.

At the Spanish CRG beamline (SpLine) located at the European Synchrotron Radiation Facility (ESRF) we have developed a complex experimental set-up dedicated to the combination of X-Ray Diffraction (XRD) and Hard X-ray Photoelectron Spectroscopy (HAXPES). For that we have developed a novel high energy electron analyzer that fulfills the requirements imposed by both techniques. The analyzer is a cylinder sector analyzer (CSA300HV) designed to operate at energies between few eV and up to 15 keV. Since one year, it is operated routinely up to 15 keV electron kinetic energy. In this work we present a detailed description of the developed electron analyzer together with the experimental determination of its intrinsic properties in terms of transmission, energy resolution and kinetic energy range achievable.

The photoemission spectroscopies play a preponderant role in the study of the electronic and compositional properties of solids. However, in standard laboratory conditions the reduced escape depth, added to low photon flux of conventional sources, make inaccessible depth profile information in a non-destructive way. In particular, the buried interfaces are not accessible for the great majority of the surface science non-destructive chemical, compositional and electronic techniques. An effective way to overcome this drawback is increasing the probing depth by analyzing electrons with a higher kinetic energy, i.e., extending the XPS to the Hard X-ray regime. Hard X-ray PhotoElectron Spectroscopy (HAXPES) is becoming an extremely powerful tool for chemical, compositional and electronic characterization of bulk and buried interfaces. A potential application of HAXPES is the determination of nondestructive compositional depth profiles in the tens nanometers scale. A methodology based on HAXPES and X-Ray Diffraction is presented through this manuscript for the determination of non-destructive compositional depth profiles.

The structural and magnetic properties of thin films and multilayers based on CoxSi1−x magnetic layers and Si spacers have been studied by surface x-ray diffraction, Auger electron spectroscopy and magneto-optical transverse Kerr effect measurements. Surface x-ray diffraction has been used to follow the evolution of the Co lattice as Si is incorporated into the network for the low Si content range, 1.00≤x≤0.77, and a contraction of the unit cell, around 0.2% out-of-plane and 0.9% in-plane, has been found. No fingerprint of structural anisotropy in the grain size, either parallel or perpendicular to the magnetic easy axis, has been detected. Magneto-optical transverse Kerr effect hysteresis loops of single films show both an increase of coercive field and a rotation of the magnetic anisotropy axis as Si enters the lattice in the polycrystalline range, 1.00≤x≤0.85. For the multilayer case, the loops confirm the formation of antiferromagnetic ordering through the layers when the composition of the alloy is tuned to be in the amorphous range. The corresponding AES signals show asymmetric depth profiles, suggesting the formation of intermediate compounds at the broader Co-on-Si interfaces.