Mauro Rovezzi

European Synchrotron Radiation Facility

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Pieter Glatzel

European Synchrotron Radiation Facility

Alain Manceau

European Synchrotron Radiation Facility

F. D’Acapito

Laboratoire Interuniversitaire des Systèmes Atmosphériques

Thibaut Devillers

Institut Néel

A. Bonanni

Johannes Kepler University of Linz

A. Navarro‐Quezada

Johannes Kepler University of Linz

T. Dietl

Czech Academy of Sciences, Institute of Physics

M. Sawicki

Polish Academy of Sciences

B. Faina

Johannes Kepler University of Linz

Isabelle Gautier‐Luneau

Centre National de la Recherche Scientifique

Cooperative Institutions

Centre National de la Recherche Scientifique

141

Université Grenoble Alpes

European Synchrotron Radiation Facility

Commissariat à l'Énergie Atomique et aux Énergies Alternatives

Institut de Recherche pour le Développement

CEA Grenoble

Université Joseph Fourier

European Science Foundation

Technical University of Denmark

Institut polytechnique de Grenoble

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TEXS: in-vacuum tender X-ray emission spectrometer with 11 Johansson crystal analyzers

Journal of Synchrotron Radiation (2020)

Mauro Rovezzi Alistair Harris Blanka Detlefs Timothy Bohdan Artem Svyazhin

We describe the design and show first results of a large solid angle X-ray emission spectrometer that is optimized for energies between 1.5 keV and 5.5 keV. The spectrometer is based on an array of 11 cylindrically bent Johansson crystal analyzers arranged in a non-dispersive Rowland circle geometry. The smallest achievable energy bandwidth is smaller than the core hole lifetime broadening of the absorption edges in this energy range. Energy scanning is achieved using an innovative design, maintaining the Rowland circle conditions for all crystals with only four motor motions. The entire spectrometer is encased in a high-vacuum chamber that allocates a liquid helium cryostat and provides sufficient space for in situ cells and operando catalysis reactors.

Cryostat

Solid angle

Crystal (programming language)

10.1107/s160057752000243x

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Citations (11)

Xraypy/Xraylarch 0.9.35Rc2

M. Newville Bruce Ravel Margaretkolbeannellen Mauro Rovezzi Nathaniel M. Beaver

10.5281/zenodo.1009624

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Electronic structure and local distortions in epitaxial ScGaN films

Journal of Physics Condensed Matter (2014)

S. M. Knoll Mauro Rovezzi Siyuan Zhang T.B. Joyce M. A. Moram

High energy resolution fluorescence-detected x-ray absorption spectroscopy and density functional theory calculations were used to investigate the local bonding and electronic structure of Sc in epitaxial wurtzite-structure ScxGa1−xN films with x ≤ 0.059. Sc atoms are found to substitute for Ga atoms, accompanied by a local distortion involving an increase in the internal lattice parameter u around the Sc atoms. The local bonding and electronic structure at Sc are not affected strongly by the strain state or the defect microstructure of the films. These data are consistent with theoretical predictions regarding the electronic structure of dilute ScxGa1−xN alloys.

Wurtzite crystal structure

Lattice (music)

10.1088/0953-8984/26/22/225801

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Citations (5)

Characterization of thermally treated Mo/Si multilayer mirrors with standing wave-assisted EXAFS

Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms (2006)

Mauro Rovezzi F. D’Acapito Alessandro Patelli V. Rigato Guido Salmaso

Characterization

Standing wave

10.1016/j.nimb.2005.12.023

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Citations (6)

Strain and correlation of self-organizedGe1−xMnxnanocolumns embedded in Ge (001)

Physical Review B (2010)

Samuel Tardif V. Favre‐Nicolin Frédéric Lançon Emmanuel Arras M. Jamet

We report on the structural properties of ${\text{Ge}}_{1\ensuremath{-}x}{\text{Mn}}_{x}$ layers grown by molecular-beam epitaxy. In these layers, nanocolumns with a high Mn content are embedded in an almost-pure Ge matrix. We have used grazing-incidence x-ray scattering, atomic force and transmission electron microscopy to study the structural properties of the columns. We demonstrate how the elastic deformation of the matrix (as calculated using atomistic simulations) around the columns, as well as the average intercolumn distance can account for the shape of the diffusion around Bragg peaks.

Matrix (chemical analysis)

10.1103/physrevb.82.104101

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Citations (16)

UV-photopolymerisation of poly(methyl methacrylate)-based inorganic–organic hybrid coatings and bulk samples reinforced with methacrylate-modified zirconium oxocluster

Polymer (2008)

Francesco Graziola Fabrizio Girardi Matthias Bauer R. Di Maggio Mauro Rovezzi

Thermogravimetric analysis

Hybrid material

Thermal Stability

10.1016/j.polymer.2008.08.005

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Citations (38)

Interface-driven magnetic anisotropies in a ferrofluid of core-shell nanoparticles

arXiv (Cornell University) (2016)

Niéli Daffé Marcin Sikora Nadejda Bouldi Véronica Gavrilov Sophie Neveu

Magnetic anisotropies in a ferrofluid of core@shell MnFe2O4@CoFe2O4 nanoparticles are studied in the liquid and frozen states using a unique sample cell developed for element specific hard X-ray magnetic spectroscopies. The MnFe2O4@CoFe2O4 6.7 nm particles reveal original magnetic properties, with a gradient in coercive field inside a nanospinel. The very thin (0.35 nm) CoFe2O4 shell is found to impose a strong magnetic anisotropy to the otherwise very soft MnFe2O4 core, so that the inner core presents a large coercive field (0.56 T) and an unexpectedly high remanent magnetization (95% of the saturation magnetization) for such a non-oriented system. The possibility to investigate ferrofluid samples where interparticle interactions have been preserved opens new perspectives in the domain of magnetic liquids.

Ferrofluid

Single domain

Saturation (graph theory)

Domain wall (magnetism)

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Ga1-xMnxN - Experimental Probing of Exchange Interactions between Localized Spins in a Dilute Magnetic Insulator

arXiv (Cornell University) (2010)

A. Bonanni M. Sawicki Thibaut Devillers W. Stefanowicz B. Faina

The sign, magnitude, and range of the exchange couplings between pairs of Mn ions is determined for (Ga,Mn)N and (Ga,Mn)N:Si with x < 3%. The samples have been grown by metalorganic vapor phase epitaxy and characterized by secondary-ion mass spectroscopy; high-resolution transmission electron microscopy with capabilities allowing for chemical analysis, including the annular dark-field mode and electron energy loss spectroscopy; high-resolution and synchrotron x-ray diffraction; synchrotron extended x-ray absorption fine-structure; synchrotron x-ray absorption near-edge structure; infra-red optics and electron spin resonance. The results of high resolution magnetic measurements and their quantitative interpretation have allowed to verify a series of ab initio predictions on the possibility of ferromagnetism in dilute magnetic insulators and to demonstrate that the interaction changes from ferromagnetic to antiferromagnetic when the charge state of the Mn ions is reduced from 3+ to 2+.

Exchange interaction

XANES

Source

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Atomic structure of Mn-rich nanocolumns probed by x-ray absorption spectroscopy

Applied Physics Letters (2008)

Mauro Rovezzi Thibaut Devillers Emmanuel Arras F. D’Acapito A. Barski

In this letter, we have used the extended x-ray-absorption fine-structure (EXAFS) technique to investigate the structure of Mn-rich self-organized nanocolumns grown by low temperature molecular beam epitaxy. The EXAFS analysis has shown that Mn-rich nanocolumns exhibit a complex local structure that cannot be described by a simple substitutional model. Additional interatomic distances had to be considered in the EXAFS model which are in excellent agreement with the structure of a Ge–3Mn building block tetrahedron of Ge3Mn5.

Tetrahedron

X-Ray Spectroscopy

X-ray absorption spectroscopy

10.1063/1.2949077

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Citations (21)

Biological Samples Preparation for Speciation at Cryogenic Temperature using High-Resolution X-Ray Absorption Spectroscopy

Journal of Visualized Experiments (2022)

Caroline Bissardon Marie‐Pierre Isaure Emmanuel Lesuisse Mauro Rovezzi Eric Lahéra

The study of elements with X-ray absorption spectroscopy (XAS) is of particular interest when studying the role of metals in biological systems. Sample preparation is a key and often complex procedure, particularly for biological samples. Although X-ray speciation techniques are widely used, no detailed protocol has been yet disseminated for users of the technique. Further, chemical state modification is of concern, and cryo-based techniques are recommended to analyze the biological samples in their near-native hydrated state to provide the maximum preservation of chemical integrity of the cells or tissues. Here, we propose a cellular preparation protocol based on cryo-preserved samples. It is demonstrated in a high energy resolution fluorescence detected X-ray absorption spectroscopy study of selenium in cancer cells and a study of iron in phytoplankton. This protocol can be used with other biological samples and other X-ray techniques that can be damaged by irradiation.

X-ray absorption spectroscopy

Biological specimen

Sample Preparation

Chemical state

10.3791/60849

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Citations (3)