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  1. AU="Yakhou-Harris, F"
  2. AU="Löffler, Bernd"
  3. AU="Kawamura, Michihiro"
  4. AU="Reinius, Björn"
  5. AU="Reis, L C"
  6. AU=Bonsignore M R
  7. AU="Millard, Glenda M"
  8. AU="Springer, Andrea"
  9. AU="Hyunho Han"
  10. AU="Grommen, Sylvia V H"
  11. AU="Asemani, Yahya"
  12. AU="Ketomäki, Tuomo"
  13. AU=Cavallini Giorgio
  14. AU="Saha, Aakash"
  15. AU="Noguchi, J"
  16. AU="Löhr, B."
  17. AU="Lokie, Kelsey B"

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  1. Artikel ; Online: Charge density waves and Fermi surface reconstruction in the clean overdoped cuprate superconductor Tl

    Tam, C C / Zhu, M / Ayres, J / Kummer, K / Yakhou-Harris, F / Cooper, J R / Carrington, A / Hayden, S M

    Nature communications

    2022  Band 13, Heft 1, Seite(n) 570

    Abstract: Hall effect and quantum oscillation measurements on high temperature cuprate superconductors show that underdoped compositions have small Fermi surface pockets whereas when heavily overdoped, a single much larger pocket is found. The origin of this ... ...

    Abstract Hall effect and quantum oscillation measurements on high temperature cuprate superconductors show that underdoped compositions have small Fermi surface pockets whereas when heavily overdoped, a single much larger pocket is found. The origin of this change in electronic structure has been unclear, but may be related to the high temperature superconductivity. Here we show that the clean overdoped single-layer cuprate Tl
    Sprache Englisch
    Erscheinungsdatum 2022-01-28
    Erscheinungsland England
    Dokumenttyp Journal Article
    ZDB-ID 2553671-0
    ISSN 2041-1723 ; 2041-1723
    ISSN (online) 2041-1723
    ISSN 2041-1723
    DOI 10.1038/s41467-022-28124-y
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  2. Artikel ; Online: Evolution of the Magnetic Excitations in Electron-Doped La_{2-x}Ce_{x}CuO_{4}.

    Li, X T / Tu, S J / Chaix, L / Fawaz, C / d'Astuto, M / Li, X / Yakhou-Harris, F / Kummer, K / Brookes, N B / Garcia-Fernandez, M / Zhou, Ke-Jin / Lin, Z F / Yuan, J / Jin, K / Dean, M P M / Liu, X

    Physical review letters

    2024  Band 132, Heft 5, Seite(n) 56002

    Abstract: We investigated the high energy spin excitations in electron-doped La_{2-x}Ce_{x}CuO_{4}, a cuprate superconductor, by resonant inelastic x-ray scattering (RIXS) measurements. Efforts were paid to disentangle the paramagnon signal from non-spin-flip ... ...

    Abstract We investigated the high energy spin excitations in electron-doped La_{2-x}Ce_{x}CuO_{4}, a cuprate superconductor, by resonant inelastic x-ray scattering (RIXS) measurements. Efforts were paid to disentangle the paramagnon signal from non-spin-flip spectral weight mixing in the RIXS spectrum at Q_{∥}=(0.6π,0) and (0.9π,0) along the (1 0) direction. Our results show that, for doping level x from 0.07 to 0.185, the variation of the paramagnon excitation energy is marginal. We discuss the implication of our results in connection with the evolution of the electron correlation strength in this system.
    Sprache Englisch
    Erscheinungsdatum 2024-02-16
    Erscheinungsland United States
    Dokumenttyp Journal Article
    ZDB-ID 208853-8
    ISSN 1079-7114 ; 0031-9007
    ISSN (online) 1079-7114
    ISSN 0031-9007
    DOI 10.1103/PhysRevLett.132.056002
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  3. Artikel ; Online: High-temperature charge density wave correlations in La

    Miao, H / Lorenzana, J / Seibold, G / Peng, Y Y / Amorese, A / Yakhou-Harris, F / Kummer, K / Brookes, N B / Konik, R M / Thampy, V / Gu, G D / Ghiringhelli, G / Braicovich, L / Dean, M P M

    Proceedings of the National Academy of Sciences of the United States of America

    2017  Band 114, Heft 47, Seite(n) 12430–12435

    Abstract: Although all superconducting cuprates display charge-ordering tendencies, their low-temperature properties are distinct, impeding efforts to understand the phenomena within a single conceptual framework. While some systems exhibit stripes of charge and ... ...

    Abstract Although all superconducting cuprates display charge-ordering tendencies, their low-temperature properties are distinct, impeding efforts to understand the phenomena within a single conceptual framework. While some systems exhibit stripes of charge and spin, with a locked periodicity, others host charge density waves (CDWs) without any obviously related spin order. Here we use resonant inelastic X-ray scattering to follow the evolution of charge correlations in the canonical stripe-ordered cuprate La
    Sprache Englisch
    Erscheinungsdatum 2017-11-21
    Erscheinungsland United States
    Dokumenttyp Journal Article
    ZDB-ID 209104-5
    ISSN 1091-6490 ; 0027-8424
    ISSN (online) 1091-6490
    ISSN 0027-8424
    DOI 10.1073/pnas.1708549114
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  4. Artikel ; Online: The high-field magnet endstation for X-ray magnetic dichroism experiments at ESRF soft X-ray beamline ID32.

    Kummer, K / Fondacaro, A / Jimenez, E / Velez-Fort, E / Amorese, A / Aspbury, M / Yakhou-Harris, F / van der Linden, P / Brookes, N B

    Journal of synchrotron radiation

    2016  Band 23, Heft 2, Seite(n) 464–473

    Abstract: A new high-field magnet endstation for X-ray magnetic dichroism experiments has been installed and commissioned at the ESRF soft X-ray beamline ID32. The magnet consists of two split-pairs of superconducting coils which can generate up to 9 T along the ... ...

    Abstract A new high-field magnet endstation for X-ray magnetic dichroism experiments has been installed and commissioned at the ESRF soft X-ray beamline ID32. The magnet consists of two split-pairs of superconducting coils which can generate up to 9 T along the beam and up to 4 T orthogonal to the beam. It is connected to a cluster of ultra-high-vacuum chambers that offer a comprehensive set of surface preparation and characterization techniques. The endstation and the beam properties have been designed to provide optimum experimental conditions for X-ray magnetic linear and circular dichroism experiments in the soft X-ray range between 400 and 1600 eV photon energy. User operation started in November 2014.
    Sprache Englisch
    Erscheinungsdatum 2016-02-20
    Erscheinungsland United States
    Dokumenttyp Journal Article
    ZDB-ID 2021413-3
    ISSN 1600-5775 ; 0909-0495
    ISSN (online) 1600-5775
    ISSN 0909-0495
    DOI 10.1107/S160057751600179X
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  5. Artikel ; Online: Stable Fe nanomagnets encapsulated inside vertically-aligned carbon nanotubes.

    Bondino, Federica / Magnano, Elena / Ciancio, Regina / Castellarin Cudia, Carla / Barla, Alessandro / Carlino, Elvio / Yakhou-Harris, Flora / Rupesinghe, Nalin / Cepek, Cinzia

    Physical chemistry chemical physics : PCCP

    2017  Band 19, Heft 47, Seite(n) 32079–32085

    Abstract: Well-defined sized (5-10 nm) metallic iron nanoparticles (NPs) with body-centered cubic structure encapsulated inside the tip of millimeter-long vertically aligned carbon nanotubes (VACNTs) of uniform length have been investigated with high-resolution ... ...

    Abstract Well-defined sized (5-10 nm) metallic iron nanoparticles (NPs) with body-centered cubic structure encapsulated inside the tip of millimeter-long vertically aligned carbon nanotubes (VACNTs) of uniform length have been investigated with high-resolution transmission electron microscopy and soft X-ray spectroscopy techniques. Surface-sensitive and chemically-selective measurements have been used to evaluate the magnetic properties of the encapsulated NPs. The encapsulated Fe NPs display magnetic remanence up to room temperature, low coercivity, high chemical stability and no significant anisotropy. Our surface-sensitive measurements combined with the specific morphology of the studied VACNTs allow us to pinpoint the contribution of the surface oxidized or hydroxidized iron catalysts present at the VACNT-substrate interface.
    Sprache Englisch
    Erscheinungsdatum 2017-12-06
    Erscheinungsland England
    Dokumenttyp Journal Article
    ZDB-ID 1476244-4
    ISSN 1463-9084 ; 1463-9076
    ISSN (online) 1463-9084
    ISSN 1463-9076
    DOI 10.1039/c7cp05181f
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  6. Buch ; Online: Three-dimensional tomographic imaging of the magnetization vector field using Fourier transform holography

    Martínez, Marisel Di Pietro / Wartelle, Alexis / Martínez, Carlos Herrero / Fettar, Farid / Blondelle, Florent / Motte, Jean-François / Donnelly, Claire / Turnbull, Luke / Ogrin, Feodor / van der Laan, Gerrit / Popescu, Horia / Jaouen, Nicolas / Yakhou-Harris, Flora / Beutier, Guillaume

    2022  

    Abstract: In recent years, interest in expanding from 2D to 3D systems has grown in the magnetism community, from exploring new geometries to broadening the knowledge on the magnetic textures present in thick samples, and with this arise the need for new ... ...

    Abstract In recent years, interest in expanding from 2D to 3D systems has grown in the magnetism community, from exploring new geometries to broadening the knowledge on the magnetic textures present in thick samples, and with this arise the need for new characterization techniques, in particular tomographic imaging. Here, we present a new tomographic technique based on Fourier transform holography, a lensless imaging technique that uses a known reference in the sample to retrieve the object of interest from its diffraction pattern in one single step of calculation, overcoming the phase problem inherent to reciprocal-space-based techniques. Moreover, by exploiting the phase contrast instead of the absorption contrast, thicker samples can be investigated. We obtain a 3D full-vectorial image of a 800 nm-thick extended Fe/Gd multilayer in a 5$\mu$m-diameter circular field of view with a resolution of approximately 80 nm. The 3D image reveals worm-like domains with magnetization pointing mostly out of plane near the surface of the sample but that falls in-plane near the substrate. Since the FTH setup is fairly simple, it allows modifying the sample environment. Therefore, this technique could enable in particular a 3D view of the magnetic configuration's response to an external magnetic field.

    Comment: 11 pages, 8 figures
    Schlagwörter Condensed Matter - Mesoscale and Nanoscale Physics ; Electrical Engineering and Systems Science - Image and Video Processing
    Thema/Rubrik (Code) 530
    Erscheinungsdatum 2022-12-20
    Erscheinungsland us
    Dokumenttyp Buch ; Online
    Datenquelle BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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  7. Artikel ; Online: Time-resolved imaging of magnetic vortex dynamics using holography with extended reference autocorrelation by linear differential operator.

    Bukin, N / McKeever, C / Burgos-Parra, E / Keatley, P S / Hicken, R J / Ogrin, F Y / Beutier, G / Dupraz, M / Popescu, H / Jaouen, N / Yakhou-Harris, F / Cavill, S A / van der Laan, G

    Scientific reports

    2016  Band 6, Seite(n) 36307

    Abstract: The magnetisation dynamics of the vortex core and Landau pattern of magnetic thin-film elements has been studied using holography with extended reference autocorrelation by linear differential operator (HERALDO). Here we present the first time-resolved x- ...

    Abstract The magnetisation dynamics of the vortex core and Landau pattern of magnetic thin-film elements has been studied using holography with extended reference autocorrelation by linear differential operator (HERALDO). Here we present the first time-resolved x-ray measurements using this technique and investigate the structure and dynamics of the domain walls after excitation with nanosecond pulsed magnetic fields. It is shown that the average magnetisation of the domain walls has a perpendicular component that can change dynamically depending on the parameters of the pulsed excitation. In particular, we demonstrate the formation of wave bullet-like excitations, which are generated in the domain walls and can propagate inside them during the cyclic motion of the vortex core. Based on numerical simulations we also show that, besides the core, there are four singularities formed at the corners of the pattern. The polarisation of these singularities has a direct relation to the vortex core, and can be switched dynamically by the wave bullets excited with a magnetic pulse of specific parameters. The subsequent dynamics of the Landau pattern is dependent on the particular configuration of the polarisations of the core and the singularities.
    Sprache Englisch
    Erscheinungsdatum 2016-10-31
    Erscheinungsland England
    Dokumenttyp Journal Article
    ZDB-ID 2615211-3
    ISSN 2045-2322 ; 2045-2322
    ISSN (online) 2045-2322
    ISSN 2045-2322
    DOI 10.1038/srep36307
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  8. Artikel ; Online: Thin conductive diamond films as beam intensity monitors for soft x-ray beamlines.

    Kummer, K / Fondacaro, A / Yakhou-Harris, F / Sessi, V / Pobedinskas, P / Janssens, S D / Haenen, K / Williams, O A / Hees, J / Brookes, N B

    The Review of scientific instruments

    2013  Band 84, Heft 3, Seite(n) 35105

    Abstract: Quantitative analysis of X-ray absorption and dichroism data requires knowledge of the beamline photon flux during the measurements. We show that thin conductive (B-doped) diamond thin films can be an alternative to the widely used gold meshes for ... ...

    Abstract Quantitative analysis of X-ray absorption and dichroism data requires knowledge of the beamline photon flux during the measurements. We show that thin conductive (B-doped) diamond thin films can be an alternative to the widely used gold meshes for monitoring the beam intensity of soft X-ray beamlines in situ. Limited by the carbon extended x-ray absorption fine structure oscillations, the diamond films become applicable beginning from about 600 eV photon energy, where the important transition metal edges and the rare-earth edges are found. The 100 nm and 250 nm thick free-standing diamond films were grown and tested against standard gold meshes in real-life dichroism experiments performed at beamline ID08 of the European Synchrotron Radiation Facility, Grenoble, France. Quantitative agreement was found between the two experimental data sets. The films feature an extremely high transmission of about 90% and, at the same time, yield a sufficiently strong and clean reference signal. Furthermore, the thin films do not affect the shape of the transmitted beam. X-rays passing mesh-type monitors are subject to diffraction effects, which widen the beam and become particularly disturbing for small beamsizes in the micrometer range.
    Sprache Englisch
    Erscheinungsdatum 2013-03
    Erscheinungsland United States
    Dokumenttyp Journal Article
    ZDB-ID 209865-9
    ISSN 1089-7623 ; 0034-6748
    ISSN (online) 1089-7623
    ISSN 0034-6748
    DOI 10.1063/1.4794439
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  9. Artikel: Persistence of magnetic excitations in La(2-x)Sr(x)CuO4 from the undoped insulator to the heavily overdoped non-superconducting metal.

    Dean, M P M / Dellea, G / Springell, R S / Yakhou-Harris, F / Kummer, K / Brookes, N B / Liu, X / Sun, Y-J / Strle, J / Schmitt, T / Braicovich, L / Ghiringhelli, G / Božović, I / Hill, J P

    Nature materials

    2013  Band 12, Heft 11, Seite(n) 1019–1023

    Abstract: One of the most intensely studied scenarios of high-temperature superconductivity (HTS) postulates pairing by exchange of magnetic excitations. Indeed, such excitations have been observed up to optimal doping in the cuprates. In the heavily overdoped ... ...

    Abstract One of the most intensely studied scenarios of high-temperature superconductivity (HTS) postulates pairing by exchange of magnetic excitations. Indeed, such excitations have been observed up to optimal doping in the cuprates. In the heavily overdoped regime, neutron scattering measurements indicate that magnetic excitations have effectively disappeared, and this has been argued to cause the demise of HTS with overdoping. Here we use resonant inelastic X-ray scattering, which is sensitive to complementary parts of reciprocal space, to measure the evolution of the magnetic excitations in La(2-x)Sr(x)CuO4 across the entire phase diagram, from a strongly correlated insulator (x = 0) to a non-superconducting metal (x = 0.40). For x = 0, well-defined magnon excitations are observed. These magnons broaden with doping, but they persist with a similar dispersion and comparable intensity all the way to the non-superconducting, heavily overdoped metallic phase. The destruction of HTS with overdoping is therefore caused neither by the general disappearance nor by the overall softening of magnetic excitations. Other factors, such as the redistribution of spectral weight, must be considered.
    Sprache Englisch
    Erscheinungsdatum 2013-08-04
    Erscheinungsland England
    Dokumenttyp Letter
    ZDB-ID 2088679-2
    ISSN 1476-4660 ; 1476-1122
    ISSN (online) 1476-4660
    ISSN 1476-1122
    DOI 10.1038/nmat3723
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  10. Artikel ; Online: Spin tuning of electron-doped metal-phthalocyanine layers.

    Stepanow, Sebastian / Lodi Rizzini, Alberto / Krull, Cornelius / Kavich, Jerald / Cezar, Julio C / Yakhou-Harris, Flora / Sheverdyaeva, Polina M / Moras, Paolo / Carbone, Carlo / Ceballos, Gustavo / Mugarza, Aitor / Gambardella, Pietro

    Journal of the American Chemical Society

    2014  Band 136, Heft 14, Seite(n) 5451–5459

    Abstract: The spin state of organic-based magnets at interfaces is to a great extent determined by the organic environment and the nature of the spin-carrying metal center, which is further subject to modifications by the adsorbate-substrate coupling. Direct ... ...

    Abstract The spin state of organic-based magnets at interfaces is to a great extent determined by the organic environment and the nature of the spin-carrying metal center, which is further subject to modifications by the adsorbate-substrate coupling. Direct chemical doping offers an additional route for tailoring the electronic and magnetic characteristics of molecular magnets. Here we present a systematic investigation of the effects of alkali metal doping on the charge state and crystal field of 3d metal ions in Cu, Ni, Fe, and Mn phthalocyanine (Pc) monolayers adsorbed on Ag. Combined X-ray absorption spectroscopy and ligand field multiplet calculations show that Cu(II), Ni(II), and Fe(II) ions reduce to Cu(I), Ni(I), and Fe(I) upon alkali metal adsorption, whereas Mn maintains its formal oxidation state. The strength of the crystal field at the Ni, Fe, and Mn sites is strongly reduced upon doping. The combined effect of these changes is that the magnetic moment of high- and low-spin ions such as Cu and Ni can be entirely turned off or on, respectively, whereas the magnetic configuration of MnPc can be changed from intermediate (3/2) to high (5/2) spin. In the case of FePc a 10-fold increase of the orbital magnetic moment accompanies charge transfer and a transition to a high-spin state.
    Mesh-Begriff(e) Circular Dichroism ; Electrons ; Indoles/chemistry ; Metals, Alkali/chemistry ; Metals, Heavy/chemistry ; Microscopy, Scanning Tunneling ; Organometallic Compounds/chemistry ; X-Ray Absorption Spectroscopy
    Chemische Substanzen Indoles ; Metals, Alkali ; Metals, Heavy ; Organometallic Compounds ; phthalocyanine (V5PUF4VLGY)
    Sprache Englisch
    Erscheinungsdatum 2014-04-09
    Erscheinungsland United States
    Dokumenttyp Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 3155-0
    ISSN 1520-5126 ; 0002-7863
    ISSN (online) 1520-5126
    ISSN 0002-7863
    DOI 10.1021/ja501204q
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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