The bonding and local atomic structure of a series of 3d metal-beta boron solid solution are investigated using a combination of x-ray absorption near-edge structure (XANES) and extended fine structure (EXAFS) technique utilizing intense synchrotron radiation as a light source. The corresponding metal diborides MB2, (M = Sc, Ti, V, Cr).were also measured and used to model the coordination environment of these metal sites in beta-boron.

The high intensities available using synchrotron source insertion devices potentially extend the range of adatom surface coverage on well prepared surfaces that may be experimentally studied to very low levels. In this paper we report the results of a fluoresence EXAFS study of a 0.5 nm thick hafnium film in the vicinity of its LIII absorption edge (9561 eV). This film was deposited on a platinum-carbon nmultilayer having a period of 31.7Å. These results indicate that EXAFS studies of species at surface coverages of 0.01 monolayer are easily experimentally accessible.

The local structure of interface or near interface impurity elements has been observed by means of extended x-ray absorption fine structure spectroscopy (EXAFS). Multilayered samples were prepared using reactive ion sputtering, electron beam evaporation , and molecular beam deposition methods with vacuum conditions ranging from 10−5 to 10−9 Pa. The interface layers of titanium, gallium, and arsenic were deposited in partial to multiple atom layers alternating with 5 to 10 nm thick matrix layers of nickel, cobalt, or aluminum. Oxide phases, atoms in solution, and local ordering were identified. Ti oxides and silicon arsenide were used as standards for the EXAFS analysis. Auger electron spectroscopy complemented the EXAFS analysis.

Conventional x-ray scattering studies have been limited to photon energies (wavelengths) in the 5 to 20 KeV (approx. 2A to 0..5A) regime. With these energies absorption lengths limit the volume of illumination to the first tens of microns of samples. If it were possible to use x-rays of very high energies, true bulk (tens of millimeters) samples could be studied. The availability, intensity and resolution possible with high energies will be discussed and their role in the expanding field of x-ray scattering presented. Preliminary studies at the Cornell High Energy Synchrotron Source (CHESS) will form the basis of these discussions.

Metastable films of fcc Fe epitaxed to Cu(001) show unusual ferromagnetic properties(1). Changes in the lattice volume occur with film thickness in the 1 to 5 monolayer range, reflecting changes in the magnitude of the spin moments and the magnetic exchange coupling. The associated uniaxial strain is manifest in strong magnetic anisotropy, layer by layer lattice expansion, phonon softening, and surface layer atomic reconstructions. We present LEED results of a detailed structural investigation, neutron reflectance measurements of the spin moments, surface magneto-optic Kerr effect studies of the magnetic anisotropy, and angle resolved photoemission of the electronic states. The observed effects are due to the strain-related kinetic energy associated with the formation of the atomic spin moments, predicted by spin-density-functional calculations of bulk fcc Fe(2).

Simple multilayer structures and multilayer diffraction gratings are now of sufficient quality to be used as optical elements in synchrotron radiation source instrumentation. In this paper results obtained with a multilayer two element monochromator will be presented. Three specific types of results will be discussed. First, transmission measurements of the absorption cross-sections of elemental thin films in the energy range 50 to 2000 eV will be presented and used to demonstrate the performance of the monochromator. Second, application of this monochromator in x-ray lithography research will be described and the advantages of the broad bandpass of multilayer optics demonstrated. Third, use of this monochromator in scattering studies of long period structures will be discussed. The potential for the use of multilayer diffraction gratings in high resolution monochromator applications will also be considered.