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6 results on '"Nick Barrett"'

1. Evolution of defect signatures at ferroelectric domain walls in Mg-doped LiNbO3

Author

Jens Kreisel, Alexander Haußmann, Nick Barrett, Mael Guennou, Guillaume F. Nataf, Laboratoire d'Etude des NanoStructures et Imagerie de Surface (LENSIS), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Materials Research and Technology (MRT) Department, Luxembourg Institute of Science and Technology (LIST), Institut für Angewandte Photophysik., Technische Universität Dresden = Dresden University of Technology (TU Dresden), Physics and Materials Science Research Unit, University of Luxembourg, University of Luxembourg [Luxembourg], and Work supported by a Pearl Grant of the National Research Funf, Luxembourg : FNR/P12/4853155

Subjects
Materials science, Annealing (metallurgy), Lithium niobate, FOS: Physical sciences, chemistry.chemical_element, doping, 02 engineering and technology, magnesium, single crystals, 01 natural sciences, symbols.namesake, chemistry.chemical_compound, Condensed Matter::Materials Science, 0103 physical sciences, General Materials Science, 010306 general physics, defects, [PHYS]Physics [physics], Condensed Matter - Materials Science, Condensed matter physics, Dopant, domain walls, Magnesium, lithium niobate, Poling, Doping, Materials Science (cond-mat.mtrl-sci), 021001 nanoscience & nanotechnology, Condensed Matter Physics, Ferroelectricity, chemistry, Raman spectroscopy, symbols, 0210 nano-technology
Abstract

The domain structure of uniaxial ferroelectric lithium niobate single crystals is investigated using Raman spectroscopy mapping. The influence of doping with magnesium and poling at room temperature is studied by analysing frequency shifts at domain walls and their variations with dopant concentration and annealing conditions. It is shown that defects are stabilized at domain walls and that changes in the defect structures with Mg concentration can be probed by the shift of Raman modes. We show that the signatures of polar defects in the bulk and at the domain walls differ., 10 pages, 3 figures

Published
2018
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2. Control of surface potential at polar domain walls in a nonpolar oxide

Author

Claire Mathieu, Jens Kreisel, D. Martinotti, Ludovic Tortech, Ekhard K. H. Salje, Pierre-Yves Hicher, Mael Guennou, Guillaume F. Nataf, Raphael Haumont, Nick Barrett, Oktay Aktas, Laboratoire d'Etude des NanoStructures et Imagerie de Surface (LENSIS), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Luxembourg Institute of Science and Technology (LIST), Physics and Materials Science Research Unit, University of Luxemburg, Laboratoire de Physico-Chimie de l'Etat Solide (CHIMSOL), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Department of Earth Sciences [University of Cambridge], University of Cambridge [UK] (CAM), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN UMR 3685), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut Parisien de Chimie Moléculaire (IPCM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Electronique et nanoPhotonique Organique (LEPO), Nataf, Guillaume [0000-0001-9215-4717], Salje, Ekhard [0000-0002-8781-6154], Apollo - University of Cambridge Repository, Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), Department of Earth Sciences, University of Cambridge, Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)

Subjects
Materials science, Physics and Astronomy (miscellaneous), FOS: Physical sciences, 02 engineering and technology, 01 natural sciences, Condensed Matter::Materials Science, chemistry.chemical_compound, Electric field, 0103 physical sciences, Microelectronics, General Materials Science, 010306 general physics, [PHYS]Physics [physics], Condensed Matter - Materials Science, Condensed matter physics, business.industry, Materials Science (cond-mat.mtrl-sci), 021001 nanoscience & nanotechnology, Polarization (waves), Ferroelectricity, Piezoelectricity, cond-mat.mtrl-sci, Calcium titanate, Ferromagnetism, chemistry, Polar, 0210 nano-technology, business
Abstract

Ferroic domain walls could play an important role in microelectronics, given their nanometric size and often distinct functional properties. Until now, devices and device concepts were mostly based on mobile domain walls in ferromagnetic and ferroelectric materials. A less explored path is to make use of polar domain walls in nonpolar ferroelastic materials. Indeed, while the polar character of ferroelastic domain walls has been demonstrated, polarization control has been elusive. Here, we report evidence for the electrostatic signature of the domain-wall polarization in nonpolar calcium titanate (CaTiO3). Macroscopic mechanical resonances excited by an ac electric field are observed as a signature of a piezoelectric response caused by polar walls. On the microscopic scale, the polarization in domain walls modifies the local surface potential of the sample. Through imaging of surface potential variations, we show that the potential at the domain wall can be controlled by electron injection. This could enable devices based on nondestructive information readout of surface potential., Comment: 30 pages, 12 figures

Published
2017
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3. Influence of hole depletion and depolarizing field on theBaTiO3/La0.6Sr0.4MnO3interface electronic structure revealed by photoelectron spectroscopy and first-principles calculations

Author

M.-A. Husanu, Cristina Chirila, Nick Barrett, Dana G. Popescu, and Iuliana Pasuk

Subjects
Local density of states, Materials science, Condensed matter physics, Schottky barrier, Fermi level, Heterojunction, Condensed Matter Physics, Manganite, 7. Clean energy, Ferroelectricity, Electronic, Optical and Magnetic Materials, Condensed Matter::Materials Science, symbols.namesake, Band bending, Superexchange, symbols, Condensed Matter::Strongly Correlated Electrons
Abstract

The effects of the bonding mechanism and band alignment in a ferroelectric (FE) BaTiO3/ferromagnetic La0.6Sr0.4MnO3 heterostructure are studied using x-ray photoelectron spectroscopy and first-principles calculations. The band lineup at the interface is determined by a combination of band bending and polarization-induced modification of core-hole screening. A Schottky barrier height for electrons of 1.22 ± 0.17 eV is obtained in the case of downwards FE polarization of the top layer. The symmetry of the bonding states is emphasized by integrating the local density of states ±0.2 eV around the Fermi level, and strong dependence on the FE polarization is found: upwards, polarization stabilizes Ti t2g(xy) orbitals, while downwards, polarization favors Ti t2g(yz) symmetry. It is predicted that the abrupt (La,Sr)|TiO2 interface is magnetoelectrically active, leading to a A-type antiferromagnetic coupling of the first TiO2 interface layer with the underlying manganite layer through a superexchange mechanism

Published
2015
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4. Investigating Electronic and Chemical Properties of Ge/GeOxNy/HfO2 Gate Stacks : High-Resolution Photoelectron Spectroscopy Using Synchrotron Radiation

Author

Lionel Fourdrinier, Olivier Renault, Corrado Crotti, Nick Barrett, Cyrille Le Royer, Laurent Clavelier, and Eugénie Martinez

Subjects
chemistry.chemical_compound, Materials science, chemistry, X-ray photoelectron spectroscopy, Band gap, Oxide, Gate stack, High resolution, Synchrotron radiation, Photon energy, Molecular physics, Spectral line
Abstract

We implemented high-resolution photoelectron spectroscopy using synchrotron radiation (160 eV photon energy) to investigate the electronics and chemistry at the interfaces of HfO2 (1 nm)/GeOxNy (0.6 nm)/Ge gate stacks. Ge3d core-level spectra show the formation of Hf-germanate at the bottom Ge oxide-high κ interface. Valence-band spectra highlight the presence of electronic N2p states in the Ge oxide band gap. The GeON/Ge valence band offset is determined as 1 eV{plus minus}0.2 eV.

Published
2006
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5. Direct quantification of gold along a single Si nanowire

Author

Thierry Baron, Nick Barrett, J. C. Cezar, F. Dhalluin, Olivier Renault, N. B. Brookes, Luiz Fernando Zagonel, Pascal Gentile, Nicolas Pauc, Aude Bailly, Amal Chabli, Surfaces, Interfaces et Nanostructures (SIN), Institut Néel (NEEL), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Service de Physique et de Chimie des Surfaces et Interfaces (SPCSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut Nanosciences et Cryogénie (INAC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Service de Physique des Matériaux et Microstructures (SP2M - UMR 9002), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire des technologies de la microélectronique (LTM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Département d'Optronique (DOPT), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), European Synchrotron Radiation Facility (ESRF), ANR-05-NANO-0065,XPEEM,Développement de la spectromicroscopie XPS par XPEEM sur nanoESCA pour les nanosciences(2005), Laboratoire d'électronique et des technologies de l'Information [Sfax] (LETI), École Nationale d'Ingénieurs de Sfax | National School of Engineers of Sfax (ENIS), Silicon Nanoelectronics Photonics and Structures (SiNaps), PHotonique, ELectronique et Ingénierie QuantiqueS (PHELIQS), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Université Joseph Fourier - Grenoble 1 (UJF)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Surfaces, Interfaces et Nanostructures (NEEL - SIN), and Clot, Marielle

Subjects
Materials science, Silicon, Scanning electron microscope, Nanowire, chemistry.chemical_element, Bioengineering, Nanotechnology, 02 engineering and technology, 01 natural sciences, Catalysis, 0103 physical sciences, General Materials Science, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], Silicon nanowires, ComputingMilieux_MISCELLANEOUS, 010302 applied physics, Mechanical Engineering, Nanostructured materials, General Chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, [PHYS.COND.CM-MS] Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Photoelectron emission microscopy, chemistry, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], 0210 nano-technology, [PHYS.COND] Physics [physics]/Condensed Matter [cond-mat]
Abstract

International audience; The presence of gold on the sidewall of a tapered, single silicon nanowire is directly quantified from core-level nanospectra using energy- filtered photoelectron emission microscopy. The uniform island-type partial coverage of gold determined as 0.42 +/- 0.06 (∼1.8 ML) is in quantitative agreement with the diameter reduction of the gold catalyst observed by scanning electron microscopy and is confirmed by a splitting of the photothresholds collected from the sidewall, from which characteristic local work functions are extracted using a model of the full secondary electron distributions.

Published
2008
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6. Structural investigation of the amorphization reaction by mechanical alloying of the Mo50Ni50 system

Author

Giorgio Cocco, Stefano Enzo, Kevin J. Roberts, and Nick Barrett

Subjects
Diffraction, Materials science, Extended X-ray absorption fine structure, General Engineering, chemistry.chemical_element, Thermodynamics, Standard enthalpy of formation, Amorphous solid, Nickel, Crystallography, chemistry, Molybdenum, Phase (matter), X-ray crystallography
Abstract

The Mo 50 Ni 50 system has been prepared by mechanical alloying, starting from a mixture of pure crystalline elements. Contrary to the case of meltquenching methods, an amorphous Mo x Ni 1− x phase has been observed after milling. A structural study by X-ray diffraction and EXAFS has shown that nickel atoms are already totally involved in the solid-state amorphization reaction after 10 h, whereas more milling time is needed to amorphize the residual crystalline b.c.c. molybdenum. Because of the relatively low ΔH for calculated according to thermodynamic models for this system, the requirement of a strong negative heat of formation as a necessary condition for amorphization does not seem to be very stringent.

Published
1989
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