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X-ray studies on the structure and magnetism of the honeycomb cobaltate Na<sub>3</sub>Co<sub>2</sub>SbO<sub>6</sub> under pressure.

ORAL

Abstract

The layered, honeycomb Na3Co2SbO6 material features Co2+ ions in trigonally distorted (Δ ∼ 40 meV) edge-shared octahedra [1,2]. The pseudospin-1/2 state of Co2+ ions together with edge-shared octahedra introduces Kitaev interactions, and it is predicted [3] that tuning Δ under isotropic compression or uniaxial strain would drive a transition from antiferromagnetically ordered to a spin liquid phase. We conducted X-ray diffraction and X-ray magnetic circular dichroism (XMCD) experiments as a function of hydrostatic pressure in a diamond anvil cell to explore the evolution of Na3Co2SbO6 structure and magnetism. Preliminary results from powder diffraction show no phase transitions up to 70 GPa. Co K-edge XMCD measurements show a robust magnetic ordering up to at least 36 GPa, with an increase in the magnetic ordering temperature with pressure. Higher hydrostatic pressures, or application of uniaxial strain in single crystalline samples, would be needed to sufficiently suppress the trigonal distortion in order to reach the postulated spin liquid phase.

[1] Viciu et al, J. Solid State Chem. 180, 1060 (2007).

[2] Yan et al, Phys. Rev. Mat. 3, 074405 (2019).

[3] Liu et al, Phys. Rev. Let. 125, 047201 (2020).

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Presenters

  • Eduardo H Poldi

    University of Illinois at Chicago

Authors

  • Eduardo H Poldi

    University of Illinois at Chicago

  • Ravhi S Kumar

    University of Illinois at Chicago, Department of Physics, University of Illinois at Chicago, University of Illinois Chicago

  • Dmitry Popov

    HPCAT, X-ray Science Division, Argonne National Laboratory, High-pressure Collaborative Access Team, Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, Argonne National Laboratory

  • Gilberto F Fabbris

    Argonne National Laboratory

  • Jiaqiang Yan

    Oak Ridge National Lab, Oak Ridge National Laboratory, ORNL

  • John F Mitchell

    Argonne National Laboratory

  • Daniel Haskel

    Argonne National Laboratory

  • Russell J Hemley

    University of Illinois Chicago, University of Illinois at Chicago, George Washington Univ, Departments of Physics and Chemistry, University of Illinois at Chicago, Department of Physics, University of Illinois at Chicago, Chicago, IL 60607, USA; Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA, Department of Physics, University of Illinois Chicago, Chicago, USA, University of Illinois at Chicago, USA