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Synthesis and Characterization of Two Quaternary Uranium Tellurides, RbTiU3Te9 and CsTiU3Te9

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posted on 2014-08-04, 00:00 authored by Matthew D. Ward, Adel Mesbah, Minseong Lee, Christos D. Malliakas, Eun Sang Choi, James A. Ibers
Black crystals of RbTiU3Te9 and CsTiU3Te9 have been synthesized at 1223 and 1173 K, respectively, by high-temperature solid-state routes. These compounds crystallize in a new structure type in space group C2h2-P21/m of the monoclinic system. The structure, which is similar to that of CsTiUTe5, consists of UTe2 layers connected into a three-dimensional framework by TiTe6 octahedra. The expanded UTe2 layers leave channels that are filled by Rb or Cs atoms. Single-crystal resistivity measurements on CsTiU3Te9 are consistent with semiconducting behavior; the calculated activation energy is 0.30(1) eV. X-ray photoelectron spectroscopic measurements on CsTiU3Te9 indicate that the compound contains U4+. From single-crystal magnetic measurements, CsTiU3Te9 is consistent with antiferromagnetic coupling between magnetic U atoms. The very low value of the effective magnetic moment of 0.56(2) μB is believed to arise from a coexistence of magnetic and nonmagnetic U atoms.

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