Phase diagram and local structure of A2Ir2O7 pyrochlore iridates

We propose a XRPD/PDF experiment on iridium pyrochlores of compositions A2Ir2O7 (with A=Pr, Nd, Sm, Gd, Dy, Ho), which display elusive magnetic ordering. We will cover all the phase diagrams on varying the ionic radius, in order to investigate the local/medium range/average structure of the selected compounds as a function of composition and temperature from below Néel temperature to RT. Structural studies are still poorly developed, in the face of extensive magneto-conductive studies, and this proposal aims to cover this gap. A twin EXAFS experiment on the same compounds at the Ir and A L3-edges is already scheduled at PETRA-III.