CPM Seminar

Probing Materials under Extreme Conditions Using Synchrotron Radiation

Serge Desgreniers

Ottawa-Carleton Institute of Physics
University of Ottawa

The development of novel methods and tools has made possible the study physical and chemical properties of materials under extreme conditions. It is now feasible to probe condensed matter under thermodynamic conditions that prevail at Earth's core and in the interiors of giant planets, namely for pressures ranging from atmosphere to several millions of bars and for temperatures reaching several thousands of degrees. Furthermore, the recent advent of second- and third-generation synchrotron radiation sources coupled with experimental methods to generate extreme conditions on condensed matter has contributed to the remarkable growth of research in the field of science at extreme conditions. In this talk, the main problems addressed in the field of physics of materials under extreme conditions are illustrated by experimental techniques used for the study of phase transitions and physical properties in dense solid oxygen. It is shown that, at high density, solid oxygen undergoes a transition from a semiconductor to a metallic state. The transition is induced by a change of molecular configuration in the solid state leading to a new high-density crystalline structure as obtained from X-ray diffraction carried out on single crystals using synchrotron radiation.