Valence instability across magnetostructural transition in USb<sub>2</sub>

ORAL

Abstract

Pressure dependent transport measurements on USb2 indicate an abrupt antiferromagnetic–ferromagnetic (AFM–FM) transition near P = 8 GPa, accompanied by a reduction in ordering temperature by more than 100 K. The AFM–FM transition has been the subject of several recent theoretical calculations, though only few experimental probes have been reported. To elucidate the behavior near this magnetic transition, we performed pressure dependent X-ray diffraction and resonant X-ray emission spectroscopy experiments on USb2. The magnetic transition coincides with a tetragonal to orthorhombic structural transition resulting in a 17% volume collapse as well as a transient f-occupation enhancement. The AFM–FM transition width determined from structural and spectroscopic measurements agrees well with previously published transport measurements and suggests a sluggish transition from about 8 to 11 GPa. Except for the enhancement across the transition region, the f-occupation decreases steadily with pressure, demonstrating the multiconfigurational nature of actinide materials.

*This work was performed under LDRD (Tracking Code 18-SI-001) and under the auspices of the US Department of Energy by Lawrence Livermore National Laboratory (LLNL) under Contract No. DE-AC52- 07NA27344.

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Presenters

  • Zachary Brubaker

    • Oak Ridge National Laboratory
    • Oak Ridge National Lab

Authors

  • Zachary Brubaker

    • Oak Ridge National Laboratory
    • Oak Ridge National Lab

  • Yuming Xiao

    • Argonne National Laboratory
    • Advanced Photon Source

  • Paul Chow

    • Argonne National Laboratory
    • Advanced Photon Source

  • Curtis Kenney-Benson

    • HPCAT, X-ray Science Division, Advanced Photon Source, Argonne National Lab
    • Argonne National Laboratory
    • Argonne Natl Lab
    • HPCAT, X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont IL, 60439, USA

  • Jesse Smith

    • Argonne National Laboratory
    • X-ray Science Division, Argonne Natl Lab

  • Hyunchae Cynn

    • Lawrence Livermore National Laboratory
    • Lawrence Livermore Natl Lab

  • Christopher Reynolds

    • Lawrence Livermore National Laboratory

  • Nicholas Butch

    • NIST Center for Neutron Research, National Institute of Standards and Technology
    • National Institute of Standards and Technology
    • Center of Neutron Research, National Institute of Standards and Technology
    • Center for Neutron Research, National Institute of Standards and Technology
    • NIST Center for Neutron Research
    • NIST center for neutron research
    • NIST
    • NIST Center for Neutron Research, National Institute of Standards and Technology,
    • University of Maryland, College Park & NIST
    • National Institute of Standards and Technology Center for Neutron Research

  • Rena Zieve

    • University of California, Davis

  • Jason R Jeffries

    • Lawrence Livermore National Laboratory