Séminaire du Lundi 27 février 2012 à 10H30

 IMPMC, Université P. et M. Curie, 4, Place Jussieu, 75005 Paris

Salle de Conférence (401), 4ème étage, Couloir 22-23, Tour 23

High-pressure synthesis & Properties under high pressure of itinerant pyrochlore-type oxides

Dr. Ayako YAMAMOTO (RIKEN, Advanced Science Institute, Saitama, JAPAN)

Pyrochlore-type compounds are known to exhibit attractive properties driven by geometrical frustration. Especially, some of the itinerant ones show superconductivity or metal-insulator transition. Here I will present my recent study in synthesis, structure and properties of A₂Ru₂O₇ (A=Hg,Cd,Ca,Tl), Tl₂Rh₂O₇, and A₂Ir₂O₇ (A=Hg,Cd,Ca,Tl). All the compounds are prepared at 4 GPa by a cubic-anvil-type equipment. High-pressure method has advantages in suppressing the vaporization of high volatile elements, stabilize unusual valence, and keeping oxygen stoichiometry. Most of ruthenium and rhodium oxides show metal-insulator transition or kink, and iridium ones show anomalous metallic feature. I will also present transport, magnetic, and structure properties under pressure of these compounds. Results show that each compound stays in balance between cations.