Neutron scattering study of breathing pyrochlore lattice material LiGaCr<sub>4</sub>S<sub>8</sub>

ORAL

Abstract

LiGaCr4S8 is a breathing pyrochlore lattice where the ordering of the Li+ and Ga3+ cations on the A-site of the spinel structure leads to the periodic expansion and contraction of Cr4 tetrahedra. Strong magneto-elastic coupling drives negative thermal expansion in the temperature range 12-110 K. Neutron diffraction and inelastic neutron scattering experiments were carried out on polycrystalline samples of LiGaCr4S8 to investigate the spin configuration and spin-spin interactions. No long-range magnetic order is observed above 1.5 K. However, neutron diffraction shows the gradual appearance of a magnetic signal centered at |Q|~0.51 Å-1 on cooling below ~100 K and a second contribution at |Q|~0.64 Å-1 appears below 15 K. The inelastic neutron scattering data shows spin excitations with a zone boundary energy 12.6 meV at 4 K. The intensity of the inelastic signal weakens above 10 K though persists to nearly 100 K. At low energies the dynamic susceptibility can be described with a single temperature dependent relaxation.

*This research is funded by
1. Gordon and Betty Moore Foundation’s EPIQS Initiative through Grant GBMF4416.
2. US Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division.

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Presenters

  • Ganesh Pokharel

    • Department of Physics & Astronomy, University of Tennessee, Knoxville, TN 37996, USA
    • Department of Materials Science and Engineering, University of Tennessee Knoxville
    • Materials Science and Engineering, University of Tennessee
    • Department of Physics & Astronomy, The University of Tennessee

Authors

  • Ganesh Pokharel

    • Department of Physics & Astronomy, University of Tennessee, Knoxville, TN 37996, USA
    • Department of Materials Science and Engineering, University of Tennessee Knoxville
    • Materials Science and Engineering, University of Tennessee
    • Department of Physics & Astronomy, The University of Tennessee

  • Hasitha Suriya Arachchige

    • Department of Physics & Astronomy, University of Tennessee, Knoxville, TN 37996, USA
    • Department of Physics and Astronomy, University of Tennessee
    • Materials Science and Engineering, University of Tennessee
    • Department of Physics & Astronomy, The University of Tennessee

  • Andrew May

    • Materials Science & Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
    • Oak Ridge National Laboratory
    • Materials Science and Technology Division, Oak-Ridge National Laboratory
    • Materials Science and Technology Division, Oak Ridge National Lab
    • Materials Science and Technology Division, Oak Ridge National Laboratory

  • Tao Hong

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

  • Stuart Calder

    • Neutron Scattering Division, Oak Ridge National Laboratory
    • Oak Ridge National Laboratory
    • Neutron Scattering Division, Oak-Ridge National Laboratory

  • Gabriele Sala

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

  • Georg Ehlers

    • Oak Ridge National Laboratory
    • Oak Ridge National Lab
    • SNS, Oak Ridge National Lab
    • Neutron Scattering Division, Oak-Ridge National Laboratory

  • David George Mandrus

    • Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
    • University of Tennessee-Knoxville
    • Oak Ridge National Lab
    • Department of Materials Science and Engineering, University of Tennessee
    • University of Tennessee (Knoxville, USA)
    • Department of Materials Science and Engineering, University of Tennessee Knoxville
    • Department of Material Science & Engineering, University of Tennessee
    • Material Science and Engineering, University of Tennessee
    • Materials Science and Technology, Materials Science and Technology
    • University of Tennessee, Knoxville
    • Department of Materials Science and Engineering, The University of Tennessee
    • Materials Science and Engineering, The University of Tennessee
    • Oak Ridge National Laboratory
    • Department of Material Science and Engineering, University of Tennessee

  • Andrew D Christianson

    • Materials Science & Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
    • Neutron Scattering Division, Oak Ridge National Laboratory
    • Materials Science and Technology Division, Oak-Ridge National Laboratory
    • Materials Science and Technology Division, Oak Ridge National Lab
    • Oak Ridge National Laboratory