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Elemental distributions of Fe, Mn, and Co in ultrathin FeMn/Co multilayers have been profiled by the x-ray anomalous scattering technique. Chemical intermixing is observed at the FeMn/Co interfaces with intermixing regions up to 14 Å. The chemical compositions in the intermixing regions are found to vary gradually from FeMn to FeMnCo[sub 2] and from FeMnCo[sub 2] to Co., respectively, but not from FeMn to Co. This result suggests that a reaction may occur and FeMnCo[sub 2] appears at the interface during the deposition. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The characteristic in-plane length scales of ultrathin films of regenerated cellulose are measured using noncontact atomic force microscopy (NC-AFM) and grazing incidence small-angle x-ray scattering (GISAXS) in ambient atmosphere and under various humidity conditions. The aim is to elucidate the structural basis for the excellent compatibility of cellulose supports to planar lipid membranes. Films are deposited on silicon wafers by Langmuir-Blodgett (LB) transfer and spin coating. NC-AFM height profiles and the resulting calculated power spectral density functions indicate that both kinds of cellulose films have almost identical root-mean-square roughness values (0.7–0.8 nm) and very similar characteristic length scales (32 nm), respectively. GISAXS measurements, both above and below the critical angle of total external reflection, show that the dominant length scales in the bulk and near the surface of the films are comparable (∼50 nm). The origin of these length scales can be attributed to the bundle of rodlike molecules of cellulose that result during the regeneration process (i.e., as a consequence of the cleavage of the silyl side chains of trimethylsilylcellulose). Exposure of the cellulose samples to various humidities shows that above a relative humidity of 97% a significant swelling of the films occurs, which is consistent with our previous findings. The swelling of films with more than 30 LB monolayers of cellulose induces a remarkable out-of-plane rearrangement of the cellulose bundles, due to a reduced influence of the solid substrate compared to thinner films with only eight to ten LB monolayers. [ABSTRACT FROM AUTHOR]

The miscibility of Ag with FePt composited films was investigated with anomalous x-ray scattering (AXS) and extended x-ray absorption fine structure (EXAFS) at Ag K edge. In the AXS spectra for FePt Bragg peaks, the cusp near Ag K edge was observed, indicating alloying between Ag and FePt in the FePt-Ag thin films. Semiquantitative analysis showed 4.2 at. % and 5.9 at. % Ag were in FePt lattice for the samples with 20 vol % and 30 vol % Ag, respectively. EXAFS studies indicated in the alloyed FePt-Ag phase, Ag replaced the Fe sites in FePt lattice. Most of Ag segregated from FePt and formed fcc phase. This segregated Ag phase only had short range order, which may be due to that segregated Ag had small grain size and/or some disordered Ag phase existed in FePt grain boundaries. [ABSTRACT FROM AUTHOR]

The phase miscibility of Co, Cr and Pt in oriented nanostructured CoCrPt magnetic thin films was investigated using anomalous x-ray scattering (AXS) from the (002) reflection and extended x-ray absorption fine structure (EXAFS) at Co K, Cr K and Pt LIII edges. The AXS measurements at Co K edge clearly showed the presence of Co in the crystalline region. However, Cr was not detected in the lattice. The EXAFS at Co K edge indicated that the nearest neighboring atoms of Co were mixed with 80% Co and 20% Pt, consistent with the results of EXAFS at Pt LIII edge. Our observations suggested that only Pt and Co were at the Co (002) lattice of the nanotextured CoCrPt thin films. This indicated that the AXS alone may not be reliable to determine the phase miscibility in textured thin films. Complementary information from the EXAFS was useful to understand the phase miscibility of nanoscale materials. [ABSTRACT FROM AUTHOR]

We have determined the absolute indium content incorporated in the crystalline lattice of InGaN films and InGaN/GaN multiple quantum wells using anomalous x-ray scattering (AXS). AXS spectra were obtained near the In K absorption edge at the InGaN (0006) Bragg peak where the InGaN Bragg reflection is well-resolved from the GaN reflections. By comparing the indium composition obtained by AXS to regular x-ray scattering results, which are also sensitive to the lattice strain, we determine the Poisson ratio of InGaN to be ν≈0.23. The AXS method can be effective in determining absolute chemical composition of InGaN independent of the lattice strain, which is especially valuable for InGaN multiple quantum wells. [ABSTRACT FROM AUTHOR]

Reports on the structure determination of nanostructured nickel-cobalt films by anomalous x-ray scattering. Structural characterization of solid solutions by conventional x-ray diffraction; Components of the atomic scattering factor; Fabrication of nanostructured metastable alloy from immiscible elements using nanoequilibrium processing.