Search

• An impact of the hydrophilic wetting on solid phonon dynamics is revealed by IXS. • Twofold impact: a depth-dependent hardening of acoustic phonons and an internal stress relaxation. • Therefore, a dynamic liquid/solid coupling is revealed, echoing mesoscopic liquid shear elasticity. We examine the influence at room temperature of the deposit of a water layer on the phonon dynamics of a solid. It is shown that the water wetting at the surface of an Alumina monocrystal has deep effects on acoustic phonons, propagating over several hundred µm distance and taking place on a relatively long time scale. The effect of the wetting at the boundary is two-fold: a hardening of both transverse and longitudinal acoustic phonons is observed as well as a relaxation of internal stresses. These acoustic phonon energy changes were observed by inelastic X-ray scattering up to 40 meV energy loss, allowing us to probe the solid at different depths from the surface. [ABSTRACT FROM AUTHOR]

• An impact of the hydrophilic wetting on solid phonon dynamics is revealed by IXS. • Twofold impact: a depth-dependent hardening of acoustic phonons and an internal stress relaxation. • Therefore, a dynamic liquid/solid coupling is revealed, echoing mesoscopic liquid shear elasticity. We examine the influence at room temperature of the deposit of a water layer on the phonon dynamics of a solid. It is shown that the water wetting at the surface of an Alumina monocrystal has deep effects on acoustic phonons, propagating over several hundred µm distance and taking place on a relatively long time scale. The effect of the wetting at the boundary is two-fold: a hardening of both transverse and longitudinal acoustic phonons is observed as well as a relaxation of internal stresses. These acoustic phonon energy changes were observed by inelastic X-ray scattering up to 40 meV energy loss, allowing us to probe the solid at different depths from the surface. [ABSTRACT FROM AUTHOR]

• Iron oxide films with variable magnetic anisotropy made by magnetron sputtering. • High resolution X-ray spectroscopy insights chemical phase composition. • Hard X-ray magnetometry extracts substrate-free magnetization profiles. • Coexistence of ferromagnetic and (super)paramagnetic components is proved. • Vertically elongated magnetite intrusions enhance perpendicular magnetic anisotropy. Texture-induced magnetic anisotropy is realized in iron oxide thin films deposited at room temperature onto Si(1 0 0) substrates using reactive magnetron sputtering of a Fe 2 O 3 target. Diversities in morphology and magnetic properties are evidenced by electron microscopy and vibrating sample magnetometry. Additional insight provided by X-ray absorption spectroscopy and X-ray magnetic circular dichroism reveals fundamental differences in chemical composition and element selective magnetic properties between the films deposited in the presence of Ar and N 2 reactive gas. Taking advantage of hard X-ray magnetometry, substrate-free magnetization profiles of the films were derived and deconvoluted into major magnetic components. In addition to ferromagnetic components with anisotropy defined by texture a significant contribution of (super)paramagnetic components due to rich interface structure of these nanocomposite films is observed. [ABSTRACT FROM AUTHOR]

Abstract: We report on the newly operational HAXPES endstation located on the GALAXIES beamline of the SOLEIL French synchrotron facility. The photon energy provided by the beamline covers the 2.4–12keV range, and electrons of kinetic energy up to 12keV can be analyzed. The HAXPES station is comprised of a UHV analysis chamber designed for investigating both solid samples and gases for the first time at high kinetic energy, and a fully equipped preparation chamber. We present the first results of X-ray photoemission and photoabsorption collected with this setup. [Copyright &y& Elsevier]

Abstract: A new hard X-ray micro-spectroscopy beamline has recently been installed at bending-magnet beamline X27A at the National Synchrotron Light Source, where the focus of research is primarily directed towards the environmental, geological and materials science communities. This instrument delivers moderate, ∼10μm spatial resolution using achromatic dynamically bent Kirkpatrick–Baez mirrors, in addition to providing high X-ray flux throughput and selectable energy resolution. The balance between moderate spatial resolution and high flux throughput, in combination with a liquid nitrogen-cooled 13-element energy-dispersive high-purity germanium detector, is particularly well suited to the investigation of dilute and thin-film systems using the fluorescence X-ray absorption fine-structure mode of detection. In this paper, we report on the design and performance of this instrument and highlight a recent experimental study undertaken at this facility. [Copyright &y& Elsevier]

Abstract: During January 2006, a new hybrid PM-type in-vacuum mini-gap undulator (MGU) with NdFeB magnets and vanadium permendur poles was installed within the X25 straight-section of the 2.8GeV National Synchrotron Light Source (NSLS) electron storage ring. This new insertion device was implemented to deliver high brightness X-ray beams within the energy range of ∼5.5–20keV for monochromatic single-crystal X-ray macromolecular crystallography. The spectral output from such a device is very sensitive to the storage ring machine parameters and in this paper, we report the precise determination of the new X25 MGU performance by implementing a single-crystal silicon (111) X-ray spectrometer to measure the X-ray energy-dependent flux throughput and infer the corresponding brightness values for a wide range of undulator gap openings. We compare these values to synchrotron radiation calculations using the SPECTRA (version 8.0) code and confirm both the integrity of the new X25 MGU device and the emittance values of the NSLS electron storage ring. [Copyright &y& Elsevier]

The National Synchrotron Light Source (NSLS) 2.8 GeV electron storage ring continues to set high standards in insertion-device research and development. The Chasman-Green NSLS lattice design provides for dispersion-free long straight sections in addition to a very small vertical β function. As the electron beam size is proportional to the square root of this function, a program to exploit this feature was undertaken more than a decade ago by implementing short-period small-gap insertion devices in the NSLS storage ring. The possibility of utilizing existing moderate-energy synchrotron radiation electron storage rings to produce high-brightness photon beams into the harder X-ray region have been realised using in-vacuum undulators. In this article the operation of a 1.25 cmperiod mini-gap undulator, operating down to a gap of 3.3 mm within the NSLS X13 straight section, is reported. It is the brightest source of hard X-rays in the energy range ∼3.7-16 kev at the NSLS, and replaces an in-vacuum undulator which had a more limited tunability. [ABSTRACT FROM AUTHOR]

Investigates the possibility of a transmission-type X-ray linear polarizer using a thin Bragg reflector as a polarizing filter. Transmitted beam as the useful output of the device; Changes in the position and direction of the transmitted beam as the energy is changed; Use of perfect crystals of silicon and diamond.

Detecting and quantifying non-bridging oxygen (NBO) atoms is of particular interest for understanding the physical properties of melts or compressed materials, and requires an unequivocal spectral signature usable during in situ measurements. In this paper, we evidence a low-energy feature of NBO in lithium silicate crystals using X-ray Raman scattering (XRS) spectroscopy around the energy losses of the oxygen K -edge. A specific peak at 534–535 eV in the edge onset is unequivocally attributed to the presence of NBO. Its intensity is used to quantify NBO in lithium silicate glasses. A similar feature at low energy has also been evidenced in Na 2 SiO 3 and MgSiO 3 , generalizing the method to other alkali and alkali-earth silicates. This non-destructive method of NBO quantification, which is based on an X-ray inelastic scattering technique, can be extended to other spectroscopies such as electron-energy loss spectroscopy, and soft X-ray absorption spectroscopy at the oxygen K edge. [ABSTRACT FROM AUTHOR]