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