Are you an EPFL student looking for a semester project?
Work with us on data science and visualisation projects, and deploy your project as an app on top of Graph Search.
We report the synthesis of single crystals of a novel layered iridate Ba21Ir9O43 and present the crystallographic, transport, and magnetic properties of this material. The compound has a hexagonal structure with two iridium oxide layers stacked along the c direction. One layer consists of a triangular arrangement of Ir2O9 dimers while the other layer comprises two regular octahedra and one triangular pyramid, forming interpenetrated triangular lattices. The resistivity as a function of temperature exhibits an insulating behavior, with a peculiar T-3 behavior. Magnetic susceptibility shows antiferromagnetic Curie-Weiss behavior with Theta(CW) similar or equal to -90 K while a magnetic transition occurs at a substantially lower temperature of 9 K. We discuss possible valence states and effective magnetic moments on Ir ions in different local environments and argue that the Ir ions in a unique triangular-pyramidal configuration likely carry unusually large magnetic moments.