Propriétés magnétiques des supraconducteurs non conventionnels epsilon-Fe, FeSe, et Ca2CuO2Cl2 étudiés par diffusion des rayons X et des neutrons

Axe 5  - Matériaux en conditions extrêmes

Thèse de Blair Lebert

Soutenue le vendredi 26 Janvier 2018 à 14H
Salle 401, 4e étage, Couloir 22-23, Tour 23,
Campus de Jussieu - Paris 5e

Laboratoires porteurs

• Institut de minéralogie, de physique des matériaux et de cosmochimie
  Porteurs de projets : Matteo D'Astuto, Stefan Klotz
• Synchrotron SOLEIL
  Porteur de projet : Jean-Pascal Rueff

Résumé

La proximité omniprésente de l'ordre magnétique et supraconducteur dans les supraconducteurs non conventionnels implique l'importance de comprendre le magnétisme dans ces matériaux. Dans ce contexte, cette thèse porte sur l'étude du magnétisme dans trois supraconducteurs non conventionnels. Les excitations magnétiques dans le système d'oxychlorure de cuivre de l'élément léger Ca2CuO₂Cl₂ ont été étudiées en fonction du dopage et de la température en utilisant principalement la diffusion inélastique résonnante aux rayons X. L'effet de la pression sur le magnétisme dans epsilon-fer et le béta-FeSe a été étudié en utilisant la spectroscopie d'émission des rayons X et la diffraction des neutrons sur poudre.

Mots clés : magnétisme, supraconductivité, Ca2CuO₂Cl₂, epsilon-fer, FeSe

Abstract

The ubiquitous proximity of magnetic and superconducting order in unconventional superconductors implies the importance of understanding magnetism in these materials. In this context, this thesis concerns the study of magnetism in three unconventional superconductors. The magnetic excitations in the light element copper oxychloride system Ca2CuO2Cl2 were studied as a function of doping and temperature using primarily resonant inelastic x-ray scattering. The effect of pressure on magnetism in ε-iron and β-FeSe was studied using x-ray emission spectroscopy and neutron powder diffraction.

Keywords : magnetism, superconductivity, Ca₂CuO₂Cl₂, epsilon-iron, FeSe

Publications

• Blair W. Lebert, Tommaso Gorni, Michele Casula, Stefan Klotz, François Baudelet, James M. Ablett, Thomas C. Hansen, Amélie Juhin, Alain Polian, Pascal Munsch, Gilles Le Marchand, Zailan Zhang, Jean-Pascal Rueff, and Matteo d’Astuto
  Epsilon iron as a spin-smectic state
  PNAS October 8, 2019 116 (41) 20280-20285; first published September 23, 2019  
  DOI : 10.1073/pnas.1904575116
• B. Lebert, M. Dean, A. Nicolaou, J. Pelliciari, M. Dantz et al.
  Resonant inelastic X-ray scattering study of spin-wave excitations in the cuprate parent compound Ca 2 CuO 2 Cl 2
  Physical Review B : Condensed matter and materials physics, American Physical Society, 2017, 95 (15), pp.155110.
  DOI : 10.1103/PhysRevB.95.155110
  Ref HAL : hal-01388544v4
• S. Klotz, Th. Strässle, B. Lebert, Matteo D'Astuto, Th. Hansen.
  High pressure neutron diffraction to beyond 20 GPa and below 1.8 K using Paris-Edinburgh load frames
  High Pressure Research, Taylor & Francis, 2016, 36 (1), pp.73-78.
  DOi : 10.1080/08957959.2015.1136624
  Ref HAL : hal-01282686v1
• P. Zimmermann, N. Bouldi, M.O.J.Y. Hunault, M. Sikora, J.M. Ablett, J-P. Rueff, B.W. Lebert, P. Sainctavit, F.M.F. de Groot, A. Juhin.
  1s2p Resonant Inelastic X-ray Scattering Magnetic Circular Dichroism as a probe for the local and non-local orbitals in CrO2
  J. Electron Spectrosc. Relat. Phenom. 14 September (2017)
  DOI : 10.1016/j.elspec.2017.08.004.
• Z. Zhang, S. Denis, B.W. Lebert, F. Bertran, P. Le Fèvre, A. Taleb-Ibrahimi, J-P. Castellan, D. Le Bolloc’h, V.L.R Jacques, Y. Sidis, B. Baptiste, C. Decorse, P. Berthet, L. Perfetti, and M. d’Astuto
  Superconductivity, pseudo-gap, and stripe correlations in high-Tc cuprates
  Phys. B 23 October (2017)
  DOI : 10.1016/j.physb.2017.10.096.
• B.W. Lebert, V. Balédent, P. Toulemonde, J.M. Ablett, S. Klotz, T. Hansen, P. Rodière, M. Raba, and J.-P. Rueff. 
  Emergent high-spin state above 7 GPa in superconducting FeSe
  (2017) arXiv:1708.04805.
• B.W. Lebert, J.-P. Rueff, S. Klotz, A. Juhin, M. Casula, J.M. Ablett, F. Baudelet, T. Strässle, T. Hansen, A. Polian, P. Munsch, G. Le Marchand, Z. Zhang, and M. d’Astuto. 
  Unveiling the mysterious magnetic state of superconducting iron under pressure
  In preparation

Conférences (invité ou contribution orale)

• “Magnetic properties of unconventional superconductors epsilon-Fe and FeSe investigated under pressure with NPD and Fe Kbeta XES”
  Invited
  SLAC National Accelerator Laboratory, LCLS group seminar (05/12/2017) — Menlo Park, USA.
• “Magnetic properties of the unconventional superconductors epsilon-Fe, FeSe, and Ca2-xNaxCuO2Cl2 investigated by x-ray and neutron scattering”
  Invited
  Karlsruhe Institute of Technology, IFP group seminar (08/11/2017) — Karlsruhe, Germany.
• “Magnetism and unconventional superconductivity”
  Institut Néel, MagSup group seminar (04/10/2017) — Grenoble, France.
• “Discovery of new high pressure magnetic phases in Fe and FeSe using x-ray emission spectroscopy”
  Invited
  AIRAPT 26 (18/08/2017) — Beijing, China.
• “Search for magnetism in epsilon-iron with neutron diffraction and x-ray emission spectroscopy”
  Invited
  54th EHPRG International Meeting (04/09/2016) — Bayreuth, Germany.
• “Unveiling the mysterious magnetic state of iron in the superconducting pressure region”
  Journée des Doctorants de l’IMPMC (13/06/2016) — Paris, France.
• “Investigation of the magnetic state of epsilon-iron in the superconducting pressure region”
  NSLS-II seminar (01/04/2016) — Upton, USA
• “Unveiling the magnetic state of iron in the superconducting pressure region”
  XAFS 16 Satellite on x-rays and magnetism (30/08/2015) — Stuttgart, Germany.
• “Unveiling the magnetic state of iron in the superconducting pressure region”
  20th International Conference of Magnetism (05/07/2015) — Barcelona, Spain.

Posters

• “Emergent high-spin state above 7 GPa in superconducting FeSe”
  13th SOLEIL Users’ Meeting (18/01/2018) — Saclay, France.
• “High temperature superconducting oxychlorides: a light element model for cuprates”
  IXS2017 (28/08/2017) — Hamburg, Germany.
• “Unveiling the mysterious magnetic state of e-iron”
  Matériaux, États Électroniques, Interactions et Couplages non-Conventionnels” (Quantum@Matisse) (30/06/2016) — Paris, France.
• “Study of iron selenides K0.8Fe1.7Se2 and TlFe1.6Se2 under pressure with XAS and XES at Fe K-edge”
  11th SOLEIL Users’ Meeting (19/01/2016) — Saclay, France.
• “Spin-wave dispersion and magnetic exchange in antiferromagnetic Ca2CuO2Cl2”
  HSC18 (14/09/2015) — Grenoble, France.
• “Spin-wave dispersion and magnetic exchange in antiferromagnetic Ca2CuO2Cl2”
  20th International Conference of Magnetism (05/07/2015) — Barcelona, Spain.
• “Unveiling the magnetic state of iron in the superconducting pressure region”
  Réunion Annuelle du Labex MATISSE (30/06/2015) — Paris, France.
• “Unveiling the magnetic state of iron in the superconducting pressure region”
  MATISSE axe 5: New challenges in Extreme Conditions (05/0/2015) — Paris, France.
• “Unveiling the magnetic state of iron in the superconducting pressure region”
  Journée des Doctorants de l’IMPMC (16/04/2015) — Paris, France.
• “Unveiling the magnetic state of iron in the superconducting pressure region”
  10th SOLEIL Users’ Meeting (22/01/2015) — Saclay, France.