Bernard BRIAT

Titre/Title :Directeur de Recherche / Research supervisor  Thème de recherche/Research theme : Matériaux photoréfractifs / Photorefractives materials  Sujet de recherche/Subject :  1966-1974 : Demonstration of the usefulness of magnetic circular dichroism (MCD) to solve a wide range of problems relevant to metallo-organic molecules, colored centres, 4f and 3d ions, 3D bulk magnetic materials or else divalent rare earth chalcogenides in thin films. 1975-1990 : Spectroscopic study of magnetic interactions among transition metal ions : pairs, triads, spin clusters, 1D (soliton mode) and 2D ferromagnetic or antiferromagnetic insulators. Growth of numerous single cristals by the Bridgman technique. since 1991 : Extensive microscopic characterization of a large number of intrinsic and extrinsic defects in photorefractive, photochromic or scintillator materials.

1960-1963 : Academic studies at « Ecole Nationale Supérieure de Chimie », Paris
1966 Ph.D Thesis at ESPCI, Paris,  « Magnetooptical rotation through absorption bands » under the direction of Jacques Badoz.
since 1971 « Directeur de Recherche » at the CNRS

Lieu de naissance / Birthplace :  Garnat sur Engièvre, Allier (03), France

Lieu d'habitation / home town and country: 75013, Paris(France)

email : briat@optique.espci.fr

1. Characterization of charge transfer bands in photorefrative CdTe:Ge,
B. Briat, K. Shcherbin, B. Farid and F. Ramaz
Optics Communications, 16, 337-340, 1998.

2. MCD and ODMR of the Bi antisite defect in BGO,
B. Briat, A. Hamri, N. Romanov, F. Ramaz, J.C. Launay, O. Thiemann and H.J. Reyher, J. Phys. : Condensed Matter, 7, 6951-59, 1995.

3. Monitoring of V2+ and V3+ in vanadium-doped CdTe : a combined MCD and EPR approach,
B. Briat, F. Ramaz, H.J. von Bardeleben, A. Hamri, J.C. Launay and V. Mazoyer, Semicon. Sc. Techn., 10,1629, 1995.

4. Double excitations of Ti-Mn spin clusters in MgCl2 , MnCl2  and MnBr2
M. Herren, M.A. Aebersold, B. Briat and H. Güdel, Inorganic Chemistry, 30, 3280, 1991.

5. Spin-dynamics and absorption band profiles for the planar 2D easy plane ferromagnet Rb2CrCl4
B. Briat, S.T. Bramwell, J.C. Canit, P. Day and J. Thorne, Proc. Roy. Soc. London, A415, 277-302, 1988.

6. Applications on magnetic circular dichroism to charge transfer and ligand field spectra
B. Briat in « Electronics States in Inorganic Compounds : New experimental Techniques », P. Day Ed., D. Reidel, Dordrecht, Holland (1975).

• 1966-1967 : Post-doctoral fellow at the Department of Chemistry (Carl Djerassi), Stanford University, California, USA. MCD (room temperature) of highly symmetrical organic (annulenes) or biologically related molecules (chlorins, vitamin B12 derivatives, porphyrins).
• July-October 1979 : Research School of Chemistry, Canberra, Australia (Jim Ferguson). Electronic and vibrational Raman study of transition metal ions and ions pairs.
• August 1980 : National Research Council, Ottawa, Canada (Dave Lockwood). Raman work.
• 1974-1985: Inorganic Chemistry Laboratory, Oxford, U.K (Peter Day).Magnetooptical study of the charge transfer bands of tetrahedral halo-ions.
• January-March 1985: Inorganic Chemistry Laboratory, Oxford, U.K (Peter Day).Optical and magnetooptical properties of the insulating ferromagnet Rb2CrCl4
• 1987-1990 :4 stays of 1-2 weeks at the "Institut für Anorganische Chemie", Bern, Switzerland (Hans Güdel). Optical studies on spin agregates
• since 1991 : One week in Osnabrück (Hans Reyher), Madrid (Carlos Zaldo), Bucharest (Vladimir Topa), Warshaw (Mietek Borowiec) and Sofia (Marin Gospodinov).

Additional collaborations(Photorefractive materials)