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Large positive zero field splitting in the cluster magnet Ba$_3$CeRu$_2$O$_9$

ORAL

Abstract

We present the synthesis and magnetic characterization of a polycrystalline sample of the 6H-perovskite Ba$_3$CeRu$_2$O$_9$, which consists of Ru dimers based on face-sharing RuO$_6$ octahedra. Our low-temperature magnetic susceptibility, magnetization and neutron powder diffraction results reveal a non-magnetic singlet ground state for the dimers. Inelastic neutron scattering, infrared spectroscopy, and the magnetic susceptibility over a wide temperature range are best explained by a molecular orbital model with a zero-field splitting parameter $D$~$=$~85~meV for the $S_{tot}$~$=$~1 electronic ground state multiplet. This large value is likely due to strong mixing between this ground state multiplet and low-lying excited multiplets, arising from a sizable spin molecular orbital coupling combined with an axial distortion of the Ru$_2$O$_9$ units. Although the positive sign for the splitting ensures that Ba$_3$CeRu$_2$O$_9$ is not a single molecule magnet, our work suggests that the search for these interesting materials should be extended beyond Ba$_3$CeRu$_2$O$_9$ to other molecular magnets based on metal-metal bonding.

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Presenters

  • Adam Aczel

    Oak Ridge National Laboratory, Oak Ridge National Lab, Neutron Scattering Division, Oak Ridge National Laboratory, Oakridge National Lab

Authors

  • Adam Aczel

    Oak Ridge National Laboratory, Oak Ridge National Lab, Neutron Scattering Division, Oak Ridge National Laboratory, Oakridge National Lab

  • Qiang Chen

    University of Tennessee

  • Shiyu Fan

    University of Tennessee, Physics, University of Tennessee, Knoxville, Physics and Astronomy, University of Tennessee, Knoxville

  • Keith Taddei

    Oak Ridge National Laboratory, Oak Ridge National Lab, Neutron Scattering Division, Oak Ridge National Laboratory, HFIR, Oak Ridge National Laboratory

  • Matthew Stone

    Oak Ridge National Lab, Neutron Scattering Division, Oak Ridge National Laboratory, Quantum Condensed Matter Div, Oak Ridge National Lab, Oak Ridge National Laboratory, Spallation Neutron Source, Oak Ridge National Laboratory, Neutron Scattering Division, Oak Ridge National Lab, Neutron Scattering Division, OakRidge National Laboratory

  • Alexander Kolesnikov

    Oak Ridge National Lab, Neutron Scattering Division, Oak Ridge National Laboratory, Neutron Scattering Division, Oak Ridge National Lab, Oak Ridge National Laboratory

  • Jinguang Cheng

    Chinese Academy of Sciences, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Chinese Academy of Sciences,Institute of Physics, Institute of Physics, Chinese Academy of Sciences

  • Janice Lynn Musfeldt

    University of Tennessee, Department of Chemistry, University of Tennessee, Knoxville, Chemistry, University of Tennessee, Knoxville, University of Tennessee, Knoxville, Chemistry, University of Tennessee, Knoxville, Tennessee, 37996, USA

  • Haidong Zhou

    University of Tennessee, Department of Physics and Astronomy, University of Tennessee, Knoxville, University of Knoxville, Tennessee, Department of Physics & Astronomy, University of Tennessee, University of Tennesse, Knoxville, Physics and anstronomy, University of Tennessee, Department of Physics, University of Tennessee, Physics, University of Tennessee, Knoxville, University of Tennessee, Knoxville