Magnetic Ordering in FeSc2S4

ORAL

Abstract

FeSc2S4 is a cubic spinel where orbitally active Fe$^{2+}$ ions occupy the A-site diamond sublattice. Despite a high spin (S=2) state and Curie Weiss temperature of 45~K thermodynamic measurements show no indication of a phase transition and the material has been proposed as a unique example of a spin-orbital liquid. This ground state might arise from competition between on site spin-orbit coupling and Kugel-Khomskii exchange. We report neutron scattering measurements on polycrystalline samples of FeSc2S4 which bring this picture into question. They reveal a previously unreported magnetically ordered state below 11 K. No structural distortions are visible with neutron or x-ray scattering. The effect of hydrostatic pressure on the magnetic excitation spectrum was also explored and found to be minimal.

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Authors

  • K.W. Plumb

    Institute for Quantum Matter and Johns Hopkins University, Johns Hopkins University

  • J.R. Morey

    Johns Hopkins University

  • J.P.C. Ruff

    CHESS, Cornell Univ, CHESS, Cornell University

  • J. A. Rodriguez-Rivera

    National Institute of Standards and Technology, NIST, NIST and Univ of Maryland, NIST Center for Neutron Research

  • Tyrel M. McQueen

    Johns Hopkins Univ, Institute for Quantum Matter and Jonhs Hopkins University, Institute for Quantum Matter and Johns Hopkins University, Johns Hopkins University, Institute for Quantum Matter, Johns Hopkins University

  • S. M. Koopayeh

    Institute for Quantum Matter and Johns Hopkins University, Johns Hopkins University, Johns Hopkins Univ, Institute for Quantum Matter, Johns Hopkins University

  • Collin Broholm

    Institute for Quantum Matter, Jonhs Hopkins University, and Quantum Condensed Matter Division, Oak Ridge National Laboratories, Johns Hopkins University, Institute for Quantum Matter and Johns Hopkins University, Johns Hopkins University, Institute for Quantum Matter, Johns Hopkins Univ