Observation of Two Magnetically Inequivalent Regions in SmB<sub>6</sub> at Low Temperatures

ORAL

Abstract

The temperature dependence of the μSR relaxation rate in SmB6 exposed to a high transverse magnetic field (TF) was recently shown to exhibit thermally-activated behavior for 4 K < T < 20 K, consistent with the freezing out of a bulk low-energy (~ 1 meV) spin exciton [K. Akintola et al., npj Quantum Materials 3:36 (2018)]. However, a 1 meV magnetic excitation has never been observed in neutron scattering measurements, all of which have been performed on the same floating-zone grown double-isotope 154Sm11B6 single crystal. In an attempt to understand why, we have performed zero-field (ZF) and longitudinal-field (LF) μSR measurements on the 154Sm11B6 and Al-flux grown SmB6 single crystals. The μSR signals show greater relaxation in the 154Sm11B6 single crystal, and reveal the development of slow and fast relaxing components below T ~ 20 K. The volume fraction of the slower relaxing component grows to ~ 70 % at T = 2 K. While the relaxation rates are smaller, the volume fractions of the two components are similar in the Al-flux grown SmB6 crystals. This suggests that the source of the two components is intrinsic and originates from spatially distinguishable regions in the sample.

*Acknowledged support from NSERC, CIFAR, AFOSR, and the Gordon & Betty Moore Foundation's EPiQS Initiative.

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Presenters

  • Jeff Sonier

    • Department of Physics, Simon Fraser University
    • Simon Fraser University

Authors

  • Jeff Sonier

    • Department of Physics, Simon Fraser University
    • Simon Fraser University

  • Kolawole Akintola

    • Department of Physics, Simon Fraser University
    • Simon Fraser University

  • Shayan Gheidi

    • Department of Physics, Simon Fraser University
    • Simon Fraser University

  • Sarah R Dunsiger

    • TRIUMF

  • Andre Cote

    • Kwantlen Polytechnic University

  • Shanta Saha

    • Physics, University of Maryland
    • Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland
    • University of Maryland, College Park & NIST
    • Department of Physics, University of Maryland, College Park
    • University of Maryland
    • University of Maryland - College Park

  • Johnpierre Paglione

    • Physics, University of Maryland
    • University of Maryland, College Park
    • Center for Nanophysics and Advanced Materials, University of Maryland College Park
    • Center for Nanophysics and Advance Materials, University of Maryland, College Park, MD
    • University of Maryland, College Park & NIST
    • Department of Physics, University of Maryland, College Park
    • University of Maryland
    • University of Maryland - College Park

  • Wesley T Fuhrman

    • Institute for Quantum Matter, Johns Hopkins University
    • Department of Physics and Astronomy, Johns Hopkins University
    • Johns Hopkins University

  • Collin Broholm

    • Johns Hopkins
    • Johns Hopkins University
    • IQM, Johns Hopkins University
    • Department of Physics and Astronomy, Johns Hopkins University