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Daniel BRAITHWAITE

PHotonique, ELectronique et Ingénierie QuantiqueS

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Head of IMAPEC Laboratory (Instrumentation, Matériaux avancés, Physique des Electrons Corrélés)

 

Research Field : Magnetism and Superconductivity in strongly correlated electron systems and extreme conditions (High pressure, low temperature, magnetic field).

I am interested in the physics of strongly correlated electron systems, mainly rare earth or uranium based intermetallic compounds. The effects we are looking for now, such as unconventional superconductivity and its interaction with magnetism, are often very subtle effects, and our competitivity in the field stems in large part from considerable instrumental developments as these studies require at least three conditions to succeed :

1/ Very pure samples, if possible single crystals. Most of the samples we study are made in the crystal growth facility in the lab.

2/ Extreme conditions of high pressure, low temperature, and sometimes magnetic field, to tune the microscopic parameters of the sample in order to explore the phase diagram and attain the new quantum phases we search for. To reach low temperatures we regularly use commercial or custom built 3He/4He dilution fridges allowing temperatures of less than 0.03K to be reached. Commercial superconducting magnets enable us to obtain fields up to 18T. However our main innovations are in the field of high pressure. We use mainly diamond anvil cells reaching pressures up to 20 GPa, but more importantly in extremely hydrostatic conditions using helium or argon as a pressure medium. We have developped techniques to introduce leads into the pressure chamber, and to change the pressure at low temperature. We also use larger volume cells, such as the Bridgman cell, which we recently modified to work woth a liquid medium, or piston cylinder cells.

3/ Sensitive measuring techniques, if possible of various kinds, in order to gain as much information as possible. The measurements that are performed at high pressure include sensitive resistivity measurements, using low temperature transformers and lock-in detection techniques, but also specific heat and magnetic susceptibilty (using an a.c. techniques). We also use more and more the powerful tool that is synchrotron radiation for high pressure studies and regularly perform experiments at the ESRF such as resonnant absorption spectroscopy to determine valence change as a function of pressure, and even resonnant magnetic x-ray scattering at high pressure.

If you are interested in doing a PhD in this field please contact me, we always have openings for good students.

 

CV

Ingénieur INSA Toulouse, DEA Université Paul Sabatier Toulouse (Physique du Solide) 1987

PhD Université Joseph Fourier Grenoble (High pressure studies of high-TC superconductors, in the CNRS Grenoble high magnetic field laboratory) 1990

Habilitation à diriger le recherches, Université Joseph Fourier, Grenoble (2002)

Post-doc at the Centre de Recherches sur les Très Basses Températures (CNRS Grenoble). Critical currents in textured high Tc superconductors (1990-1992)

Post-doc at the Institute for Transuraniun compounds, Karlsruhe. Superconductivity of americium metal at high pressure (1993-1994)

Since 1994 Researcher in the Service de Physique Statistique, Magnétisme et Supraconductivité CEA/Grenoble.

Since 2008 Head of the group IMAPEC (Instrumentation, advanced materials, physics of correlated electrons)

 

Some recent publications

 

"Ferromagnetism in YbCu2Si2 at high pressure." Fernandez-Pañella, A., D. Braithwaite, et al. (2011).  Physical Review B 84(13).

 

"Thermodynamic phase diagram of Fe(Se0.5Te0.5) single crystals in fields up to 28 tesla." Klein, T., D. Braithwaite, A. Demuer, W. Knafo, G. Lapertot, C. Marcenat, P. Rodiere, I. Sheikin, P. Strobel, A. Sulpice and P. Toulemonde (2010). Physical Review B 82(18).

 

"Evidence for Anisotropic Vortex Dynamics and Pauli Limitation in the Upper Critical Field of FeSe1-xTex." Braithwaite, D., G. Lapertot, W. Knafo and I. Sheikin (2010). Journal of the Physical Society of Japan 79(5).

 

"Thermodynamic phase diagram of Fe(Se0.5Te0.5) single crystals in fields up to 28 tesla." Klein, T., D. Braithwaite, A. Demuer, W. Knafo, G. Lapertot, C. Marcenat, P. Rodiere, I. Sheikin, P. Strobel, A. Sulpice and P. Toulemonde (2010). Physical Review B 82(18).

 

Simple adaptation of the Bridgman high pressure technique for use with liquid media. E. Colombier and D. Braithwaite. Rev. Sci. Instrum. 78, 093903 (2007)

 

Antiferromagnetic order in pure CeFe2 under pressure . D. Braithwaite, G. Lapertot, B. Salce, A. –M. Cumberlidge and P. L. Alireza.  Phys. Rev B76 224427 (2007) 

 

High-pressure resonant magnetic X-ray diffraction and transport experiments in Ce(Fe1-xCox)2 . Braithwaite-D; Paolasini-L; Deen-PP; Kernavanois-N; Yakhou-F; Canfield-P; Lapertot-G . Physica-B. 1 May 2006; 378-380: 782-3

 

 

Nature of the double superconducting transition in PrOs4Sb12?  Measson-M-A; Braithwaite-D; Salce-B;Flouquet-J; Lapertot-G; Pecaut-J; Seyfarth-G; Brison-J-P; Sugawara-H; Sato-H . Physica-B. 1 May 2006; 378-380: 56-7 

 

 

Enseignement

 

Divers

 

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