R. Brochu
University of Bordeaux
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Featured researches published by R. Brochu.
Materials Research Bulletin | 1981
C. Delmas; R. Olazcuaga; G. Le Flem; Paul Hagenmuller; F. Cherkaoui; R. Brochu
Abstract A crystal chemistry study of the three solid solutions Na1+xZr2−xLx(PO4)3 (L = Cr, In, Yb) has been carried out. A Nasicon-type phase is obtained in the range 0 ⩽ x ⩽ xmax.L with xmax.Cr = 2.0, xmax.In = 1.85, xmaxYb = 1.90 at 950°C. All phases have rhombohedral symmetry except Na3Cr2(PO4)3, where a small monoclinic distortion appears at low temperature. Influence of cationic size, electrostatic repulsion and sodium distribution is discussed.
Journal of Solid State Chemistry | 1991
M. Alami; R. Brochu; J.L. Soubeyroux; P. Gravereau; G. Le Flem; P. Hagenmuller
Abstract LiGe2(PO4)3 belongs to the Nasicon-type family. Room-temperature structure has been determined on a single crystal from 3D X-ray data. Thermal evolution of this structure has been established from neutron powder diffraction data between 300 and 1000 K using the Rietveld method. The thermal expansion is positive along the c-axis, whereas shrinking is observed along the a-axis below 900 K, followed by dilatation. The atomic displacements noted with increasing temperature are consistent with a model proposed for NaZr2(PO4)3.
Materials Research Bulletin | 1981
C. Delmas; J.C. Viala; R. Olazcuaga; G. Le Flem; Paul Hagenmuller; F. Cherkaoui; R. Brochu
Abstract Ionic conductivity measurements in the solid solution Na1+xZr2−xLx(PO4)3 (L = Cr, Yb) have been carried out. The materials have a Nasicon-type structure in a 0 ⩽ x ⩽ xmax.L range (xmax.Cr = 2.0 and xmax.Yb = 1.9). A small monoclinic distortion appears at low temperature for Na3Cr2(PO4)3. As in the Na1+xZr2P3−xSixO12 system a strong increase of the conductivity with rising x has been observed. The results are discussed in connection with temperature and structural parameters.
Journal of Solid State Chemistry | 1987
A. El Jazouli; M. Alami; R. Brochu; J.M. Dance; G. Le Flem; Paul Hagenmuller
Abstract A new family of Nasicon-like zirconium phosphates of formula M 0.5 Zr 2 (PO 4 ) 3 with M = Ca, Cu, Sr, Cd or Pb has been described. The physical properties of the copper compound have been investigated in detail in which Cu 2+ induces a Jahn-Teller distortion below 520°C. Crystal field, electron paramagnetic resonance, and magnetic data are consistent with an elongated octahedral surrounding of the Cu 2+ ions.
Journal of Alloys and Compounds | 1992
M. Alami; R. Brochu; C. Parent; L. Rabardel; C. Delmas; G. Le Flem
Abstract A new phase Eu 1/3 Zr 2 (PO 4 ) 3 of Nasicon type structure was prepared via a sol-gel route. The crystallization process was investigated using Eu 3+ as a structural probe. The decomposition of this phase at 900° C leads to a complex ceramic exhibiting a very low thermal expansion coefficient between room temperature and 1340° C : ≈ 1 × 10 −1 ° C −1 . Chemical intercalation of lithium gives rise to a new Eu 2+ -rich phosphate Li x Eu 1/3 Zr 2 (PO 4 ) 3 ( x ≈ 0.33).
Journal of Solid State Chemistry | 1994
M.Alami Talbi; R. Brochu; C. Parent; L. Rabardel; G. Le Flem
Journal of Alloys and Compounds | 1997
J.M. Heintz; L. Rabardel; M. Al Qaraoui; M.Alami Talbi; R. Brochu; G. Le Flem
Powder Diffraction | 1997
A. El-Yacoubi; R. Brochu; A. Serghini; M. Louër; M. Alami Talbi; D. Louër
ChemInform | 1979
C. Delmas; R. Olazcuaga; F. Cherkaoui; R. Brochu; G. Le Flem
ChemInform | 1988
M. Alami; R. Brochu; C. Parent; G. Le Flem