A5078535244- Advanced X-ray Imaging Techniques
- Magnetic properties of thin films
- X-ray Diffraction in Crystallography
- Quasicrystal Structures and Properties
- Advanced Electron Microscopy Techniques and Applications
- Crystallography and Radiation Phenomena
- Advanced Condensed Matter Physics
- Magnetic Properties and Applications
- Magnetic and transport properties of perovskites and related materials
- Characterization and Applications of Magnetic Nanoparticles
- Crystal Structures and Properties
- Physics of Superconductivity and Magnetism
- Theoretical and Computational Physics
- Geomagnetism and Paleomagnetism Studies
- Multiferroics and related materials
- Analytic and geometric function theory
- GaN-based semiconductor devices and materials
- X-ray Spectroscopy and Fluorescence Analysis
- Electron and X-Ray Spectroscopy Techniques
- Solid-state spectroscopy and crystallography
- Microstructure and mechanical properties
- nanoparticles nucleation surface interactions
- Force Microscopy Techniques and Applications
- Optical and Acousto-Optic Technologies
- Magnetic Field Sensors Techniques
Université Grenoble Alpes
2012-2025
Science et Ingénierie des Matériaux et Procédés
2015-2024
Centre National de la Recherche Scientifique
2011-2022
Institut polytechnique de Grenoble
2010-2020
Ben-Gurion University of the Negev
2016
Université Joseph Fourier
2010-2014
Diamond Light Source
2008-2014
Institut Nanosciences et Cryogénie
2009-2011
Institut Fresnel
2011
Aix-Marseille Université
2011
Interfaces between polarity domains in nitride semiconductors, the so-called Inversion Domain Boundaries (IDB), have been widely described, both theoretically and experimentally, as perfect interfaces (without dislocations vacancies). Although ideal planar IDBs are well documented, understanding of their configurations interactions inside crystals relies on perfect-interface assumptions. Here, we report microscopic configuration n-doped gallium wires revealed by coherent X-ray Bragg imaging....
The evolution of the sign Dzyaloshinskii-Moriya interaction is determined with phase sensitive x-ray magnetic diffraction, through interference between quadrupole resonant and non-resonant scattering.
We demonstrate magnetic lensless imaging by Fourier transform holography using extended references.A narrow slit milled through an opaque gold mask is used as a holographic reference and contrast obtained x-ray circular dichroism.We present images of domains in Co/Pt multilayer thin film with perpendicular anisotropy.This technique holds advantages over standard holography, where small holes are to define the beam.An increased intensity reduces counting time record farfield diffraction...
Crystal defects induce strong distortions in diffraction patterns. A single defect alone can yield and fine features that are observed high-resolution experiments such as coherent X-ray diffraction. The case of face-centred cubic nanocrystals is studied numerically the signatures typical close to Bragg positions identified. Crystals a few tens nanometres modelled with realistic atomic potentials 'relaxed' after introduction well defined pure screw or edge dislocations, Frank prismatic loops....
Structural quality and stability of nanocrystals are fundamental problems that bear important consequences for the performances small-scale devices. Indeed, at nanoscale, their functional properties largely influenced by elastic strain depend critically on presence crystal defects. It is thus prime importance to be able monitor, noninvasive means, microstructure nano-objects against external stimuli such as mechanical load. Here we demonstrate potential Bragg coherent diffraction imaging...
Polarized x-rays allow for imaging birefringent or dichroic properties of materials with nanometric resolution. To disentangle these from the electronic density, either a polarization analyzer several measurements different polarizations (typically two more) are needed. Here we demonstrate that ptychography can single measurement by using multimodal analysis. This new method provides an alternative to obtain polarization-resolved images sample when manipulating incident is not possible...
A compact scanning force microscope has been developed for in situ combination with nanofocused X-ray diffraction techniques at third-generation synchrotron beamlines. Its capabilities are demonstrated on Au nano-islands grown a sapphire substrate. The new device allows imaging the sample topography and crystallinity by recording simultaneously an atomic (AFM) image map of same area. Moreover, selected island can be mechanically deformed using AFM tip while monitoring deformation lattice...
Crystallographic defects such as dislocations can significantly alter material properties and functionality. However, imaging these imperfections during operation remains challenging due to the short length scales involved reactive environments of interest. Bragg coherent diffractive (BCDI) has emerged a powerful tool capable identifying dislocations, twin domains, other in 3D detail with nanometer spatial resolution within nanocrystals grains environments. BCDI relies on phase retrieval...
Abstract The magnetisation dynamics of the vortex core and Landau pattern magnetic thin-film elements has been studied using holography with extended reference autocorrelation by linear differential operator (HERALDO). Here we present first time-resolved x-ray measurements this technique investigate structure domain walls after excitation nanosecond pulsed fields. It is shown that average a perpendicular component can change dynamically depending on parameters excitation. In particular,...
We have used x-ray resonant magnetic scattering at the Tb ${L}_{2}$ edge to elucidate nature of ordering in Cd${}_{6}$Tb, a 1/1 approximant closely related Cd-Mg-R (R = rare earth) icosahedral alloys. Below ${T}_{N}\ensuremath{\approx}24$ K, ordered moments associated with clusters corners and body center pseudocubic unit cell are antiferromagnetically correlated, long-range order is realized.
The authors present a new tomographic technique, based on Fourier transform holography. It is lensless imaging technique to retrieve the object of interest from its diffraction pattern in single step computation. A combination dual-axis projections provides 3D vectorial magnetic image an 800-$n\phantom{\rule{0}{0ex}}m$-thick Fe/Gd multilayer 5-$\ensuremath{\mu}\phantom{\rule{0}{0ex}}m$-diameter field view with resolution 80 $n\phantom{\rule{0}{0ex}}m$. reconstruction reveals not only...
Mechanical deformation of a SiGe island epitaxically grown on Si(001) was studied by specially adapted atomic force microscope and nanofocused X-ray diffraction. The monitored during in situ mechanical loading recording three-dimensional reciprocal-space maps around selected Bragg peak. Scanning the energy incident beam instead rocking sample allowed safe reliable measurement without removal load. crystal truncation rods originating from side facets rotate to steeper angles with increasing...
Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation S. P. Collins, A. Bombardi, R. Marshall, J. H. Williams, G. Barlow, Day, M. Pearson, Woolliscroft, D. Walton, Beutier, Nisbet; Diamond Beamline I16 (Materials Magnetism). AIP Conference Proceedings 23 June 2010; 1234 (1): 303–306. https://doi.org/10.1063/1.3463196 Download citation file: Ris (Zotero) Reference...
Electrical resistivity, specific heat, magnetic susceptibility, and magnetization of the crystalline approximant Cd${}_{6}$Sm are investigated in a temperature range 1.8\ensuremath{-}300 K. Both structural transitions clearly evidenced. A sharp phase transition is observed at ${T}_{\mathrm{c}}$ $=$ 179 K electrical resistivity as well which attributed to orientational ordering Cd${}_{4}$ tetrahedron located center icosahedral cluster. In addition, three successive found ${T}_{\mathrm{M}1}$...
We present a method to determine the magnetic configuration of an in-plane magnetized permalloy layer using Fourier transform holography with extended references in off-normal geometry. use narrow slit as holographic reference record holograms sample surface orthogonal incident x-ray beam, well rotated by 30° and 45° respect beam. To demonstrate sensitivity technique magnetization, we images flux closed ground states thin (∼50 nm) elements, less than 1 μm lateral size. Images domain pattern...
We report on the six-dimensional (6D) structural refinement of three members i-$R$-Cd quasicrystals ($R$ = Gd, Dy, Tm) via synchrotron x-ray diffraction from single-grain samples, and show that this series is isostructural to i-${\mathrm{YbCd}}_{5.7}$ quasicrystal. However, our refinements suggest $R$ occupancy Yb icosahedron sites within Tsai-type atomic cluster approximately 80%, with balance taken up by Cd. Similarities between i-${\mathrm{ScZn}}_{7.33}$, their differences...
KH2PO4 (KDP) belongs to the class of hydrogen-bonded ferroelectrics, whose paraelectric ferroelectric phase transition is driven by ordering protons in hydrogen bonds. We demonstrate that forbidden reflections KDP, when measured at an x-ray absorption edge, are highly sensitive asymmetry proton configurations. The change average symmetry caused "freezing" during clearly evidenced. In phase, we identify resonant spectra a contribution related transient configurations bonds, which violates...
The commensurate phase of multiferroic ${\text{HoMn}}_{2}{\text{O}}_{5}$ was studied by x-ray magnetic scattering, both off-resonance and in resonant conditions at the $\text{Ho}\text{ }{L}_{3}$ edge. Below 40 K, ordering Ho sites is induced main Mn order parameter, its temperature dependence well accounted for a simple Curie--Weiss susceptibility model. A lattice distortion periodicity twice that also evidenced. azimuthal scans confirm model structure recently refined from neutron...
Resonant Elastic X-Ray Scattering (REXS) has played a fundamental role in understanding electronic properties and revealing hidden order, local symmetries exotic states realized correlated solids. This article reports on some of the relevant scientific contributions technical advances over last 20 years, by providing list related publications produced various groups all around world. The given perspective is that group young scientists involved at times investigation beauty ordering REXS technique.
Abstract It has generally been accepted that the orientational ordering of Cd4 tetrahedron within Cd6 R quasicrystal approximants is kinetically inhibited for = Ho, Er, Tm and Lu by steric constraints. Our high-resolution X-ray scattering measurements Cd6Ho approximant, however, reveal an abrupt (first-order) transition to a monoclinic structure below T S 178 K samples have ‘aged’ at room temperature approximately one year, reopening this question. Using resonant magnetic Ho L 3-edge we...
We report resonant x-ray scattering measurements on a single crystal of the orbitally degenerate triangular metallic antiferromagnet $2H\mathrm{\text{\ensuremath{-}}}{\mathrm{AgNiO}}_{2}$ to probe spontaneous transition triple-cell superstructure at temperatures below ${T}_{S}=365\text{ }\text{ }\mathrm{K}$. observe strong enhancement supercell reflections through Ni $K$ edge. The empirically extracted $K$-edge shift between crystallographically distinct sites 2.5(3) eV is much larger than...
The structure of the quasicrystalline approximant ${\mathrm{Al}}_{13}{\mathrm{Co}}_{4}$(100) has been determined by surface x-ray diffraction (SXRD) and complementary density-functional-theory (DFT) calculations. Thanks to use a two-dimensional pixel detector, which speeds up data acquisition enormously, an exceptionally large set experimental data, consisting 124 crystal truncation rods, collected used refine this complex unit cell low symmetry. Various models were considered for SXRD...