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Download fileIridate Li8IrO6: An Antiferromagnetic Insulator
journal contribution
posted on 2021-11-04, 20:29 authored by Callista
M. Skaggs, Peter E. Siegfried, Chang-Jong Kang, Craig M. Brown, Fu Chen, Lu Ma, Steven N. Ehrlich, Yan Xin, Mark Croft, Wenqian Xu, Saul H. Lapidus, Nirmal J. Ghimire, Xiaoyan TanA polycrystalline
iridate Li8IrO6 material
was prepared via heating Li2O and IrO2 starting
materials in a sealed quartz tube at 650 °C for 48 h. The structure
was determined from Rietveld refinement of room-temperature powder
neutron diffraction data. Li8IrO6 adopts the
nonpolar space group R3̅ with Li atoms occupying
the tetrahedral and octahedral sites, which is supported by the electron
diffraction and solid-state 7Li NMR. This results in a
crystal structure consisting of LiO4 tetrahedral layers
alternating with mixed IrO6 and LiO6 octahedral
layers along the crystallographic c-axis. The +4
oxidation state of Ir4+ was confirmed by near-edge X-ray
absorption spectroscopy. An in situ synchrotron X-ray diffraction
study of Li8IrO6 indicates that the sample is
stable up to 1000 °C and exhibits no structural transitions.
Magnetic measurements suggest long-range antiferromagnetic ordering
with a Néel temperature (TN) of
4 K, which is corroborated by heat capacity measurements. The localized
effective moment μeff (Ir) = 1.73 μB and insulating character indicate that Li8IrO6 is a correlated insulator. First-principles calculations support
the nonpolar crystal structure and reveal the insulating behavior
both in paramagnetic and antiferromagnetic states.
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sealed quartz tuberay absorption spectroscopyprinciples calculations supportnonpolar space groupheat capacity measurements650 ° c1000 ° csitu synchrotron xray diffraction studyoctahedral layers alonginsulating character indicaterange antiferromagnetic orderingnonpolar crystal structurecrystal structure consistingeff subb sub8 sub6 sub2 subli atoms occupying4 + suptetrahedral layers alternating4 sub7 sup4 oxidation statepolycrystalline iridate lic 4 kiridate li>< subr octahedral sitesinsulating behaviorelectron diffractionedge xantiferromagnetic statesantiferromagnetic insulatorli nmrstructural transitionsstarting materialsrietveld refinementcorrelated insulator>- axis73 μ48 h3 ̅