CRYSTALLOGRAPHY AT HIGH PRESSURE AND HIGH TEMPERATURE USING THE PARIS-EDINBURGH PRESS AT THE ESRF

M. Mezouar1, S. Le Floch2, P. Bordet2, P. Toulemonde2, A. Prat2, R. Argoud2,J. J. Capponi2

1European Synchrotron Radiation Facility, B.P. 220 38000 Grenoble France
2CNRS, laboratoire de cristallographie, B.P. 166 38042 Grenoble cedex 09 France

A fast imaging plate has been interfaced for the first time to the Paris-Edinburgh press for the rapid collection of in situ X ray powder diffraction data suitable for structural refinement at high pressure and high temperature. The rapid acquisition of high quality 2D images allows time resolved studies in one minute range and gives access to the kinetics of phases formation and chemical reaction. From a general point of view, the possibility to perform fine crystallography at HP-HT does open a new field of investigation. Thanks to this new set-up, several experiments have already been successfully performed. The presentation will be focused on the crystallographic aspects of phase formations. Several examples will be presented such as : strain effect on the high pressure phase of the III-V semiconductor GaSb, mechanisms of polymerisation and deformation of the C60 at high pressure and high temperature and special emphasise will be done on the formation processes of the high Tc superconducting compounds HgBa2CuO4+d and HgBa2Ca2Cu3O8+d from the complex mixing precursors : BaCuO2 , Ca2CuO3 and HgO at high pressure (2 to 4 GPa) and high temperature (up to 1200°C).