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Possibility of an unconventional spin state of Ir4+ in Ba21Ir9O43 single crystal

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Author Yang L., Jeong M., Arakcheeva A., Zivkovic I., Nafradi B., Magrez A., Pisoni A., Jacimovic J., Katukuri V. M., Katrych S., Shaik N. E., Yazyev O. V., Forro L., Ronnow H. M.,
Project Mott Physics Beyond the Heisenberg Model in Iridates and Related Materials
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Original article (peer-reviewed)

Volume (Issue) 94(10)
Page(s) 104403
Title of proceedings PHYSICAL REVIEW B
DOI 10.1103/physrevb.94.104403

Open Access

Type of Open Access Repository (Green Open Access)


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.